We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Fix CROTA in EUVI map source
e.g. 
```python
from sunpy.map import Map

smap = Map('https://stereo-ssc.nascom.nasa.gov/pub/beacon/ahead/secchi/img/euvi/20210107/20210107_001615_n7euA.fts')
print(smap.wcs)
```
raises
```
WARNING: FITSFixedWarning: CROTA = -6.39331135705 
keyword looks very much like CROTAn but isn't. [astropy.wcs.wcs]
```
It would be good to fix this in the EUVI map source.

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `sunpy/map/sources/stereo.py`
Content:
```
1 """STEREO Map subclass definitions"""
2 
3 __author__ = "Keith Hughitt"
4 __email__ = "keith.hughitt@nasa.gov"
5 
6 
7 import astropy.units as u
8 from astropy.visualization import PowerStretch
9 from astropy.visualization.mpl_normalize import ImageNormalize
10 
11 from sunpy.map import GenericMap
12 from sunpy.map.sources.source_type import source_stretch
13 
14 __all__ = ['EUVIMap', 'CORMap', 'HIMap']
15 
16 
17 class EUVIMap(GenericMap):
18     """STEREO-SECCHI EUVI Image Map
19 
20     EUVI is an extreme ultraviolet (EUV) imager. Part of the STEREO-SECCHI
21     suite it observes the Sun from 1 to 1.7 solar radii. It is capable of
22     observing at 304 (He II), 171 (Fe IX), 195 (Fe XII), and 284 (Fe XV)
23     Angstroms.
24 
25     References
26     ----------
27     * `STEREO Mission Page <https://stereo.gsfc.nasa.gov/>`_
28     * `STEREO SECCHI <http://secchi.nrl.navy.mil>`_
29     * `Instrument Page <http://secchi.lmsal.com/EUVI/>`_
30     """
31 
32     def __init__(self, data, header, **kwargs):
33 
34         GenericMap.__init__(self, data, header, **kwargs)
35         self._nickname = "{}-{}".format(self.detector, self.observatory[-1])
36         self.plot_settings['cmap'] = 'sohoeit{wl:d}'.format(wl=int(self.wavelength.value))
37         self.plot_settings['norm'] = ImageNormalize(
38             stretch=source_stretch(self.meta, PowerStretch(0.25)), clip=False)
39         self.meta['waveunit'] = 'Angstrom'
40 
41         # Try to identify when the FITS meta data does not have the correct
42         # date FITS keyword
43         if ('date_obs' in self.meta) and not('date-obs' in self.meta):
44             self.meta['date-obs'] = self.meta['date_obs']
45 
46     @property
47     def rsun_arcseconds(self):
48         """
49         Radius of the sun in arcseconds.
50 
51         References
52         ----------
53         https://sohowww.nascom.nasa.gov/solarsoft/stereo/secchi/doc/FITS_keywords.pdf
54         """
55         return self.meta.get('rsun', None)
56 
57     @property
58     def rsun_obs(self):
59         """
60         Radius of the sun in arcseconds as a quantity.
61 
62         References
63         ----------
64         https://sohowww.nascom.nasa.gov/solarsoft/stereo/secchi/doc/FITS_keywords.pdf
65         """
66         rsun_arcseconds = self.meta.get('rsun', None)
67 
68         if rsun_arcseconds is None:
69             rsun_arcseconds = super().rsun_obs
70 
71         return u.Quantity(rsun_arcseconds, 'arcsec')
72 
73     @classmethod
74     def is_datasource_for(cls, data, header, **kwargs):
75         """Determines if header corresponds to an EUVI image"""
76         return header.get('detector') == 'EUVI'
77 
78 
79 class CORMap(GenericMap):
80     """STEREO-SECCHI CORonograph Image Map.
81 
82     Part of the STEREO-SECCHI suite of remote sensing telescopes,
83     COR is a set of two coronographs (COR1, COR2) onboard STEREO.
84     They are both traditional Lyot coronagraphs.
85 
86     The COR1 detectors observes from 1.3 to 4 solar radii while the
87     COR2 detectors observe a range from 2 to 15 solar radii.
88 
89     References
90     ----------
91     * `STEREO Mission Page <https://stereo.gsfc.nasa.gov/>`_
92     * `STEREO SECCHI <http://secchi.nrl.navy.mil>`_
93     * `COR1 Instrument Page <https://cor1.gsfc.nasa.gov>`_
94     * `COR2 Instrument Page <http://secchi.nrl.navy.mil/index.php?p=cor2>`_
95     * `COR1 User Guide <https://cor1.gsfc.nasa.gov/guide/>`_
96     """
97 
98     def __init__(self, data, header, **kwargs):
99 
100         GenericMap.__init__(self, data, header, **kwargs)
101 
102         self._nickname = "{}-{}".format(self.detector, self.observatory[-1])
103         self.plot_settings['cmap'] = 'stereocor{det!s}'.format(det=self.detector[-1])
104         self.plot_settings['norm'] = ImageNormalize(
105             stretch=source_stretch(self.meta, PowerStretch(0.5)), clip=False)
106 
107         # Try to identify when the FITS meta data does not have the correct
108         # date FITS keyword
109         if ('date_obs' in self.meta) and not('date-obs' in self.meta):
110             self.meta['date-obs'] = self.meta['date_obs']
111 
112     @property
113     def measurement(self):
114         """
115         Returns the type of data observed.
116         """
117         # TODO: This needs to do more than white-light.  Should give B, pB, etc.
118         return "white-light"
119 
120     @classmethod
121     def is_datasource_for(cls, data, header, **kwargs):
122         """Determines if header corresponds to an COR image"""
123         return str(header.get('detector', '')).startswith('COR')
124 
125 
126 class HIMap(GenericMap):
127     """STEREO-SECCHI Heliospheric Imager (HI) Map.
128 
129     The HI is a wide-angle visible-light imaging system
130     for the detection of coronal mass ejection (CME) events
131     in interplanetary space and, in particular, of events
132     directed towards the Earth.
133 
134     The Heliospheric imager consists of two instruments, the HI-1 and HI-2.
135     The HI1 observes from 15-80 solar radii while HI2 observes from 80-215
136     solar radii.
137 
138     References
139     ----------
140     * `STEREO Mission Page <https://stereo.gsfc.nasa.gov/>`_
141     * `STEREO SECCHI <https://secchi.nrl.navy.mil>`_
142     * `HI Instrument Page <http://www.stereo.rl.ac.uk>`_
143     """
144 
145     def __init__(self, data, header, **kwargs):
146 
147         GenericMap.__init__(self, data, header, **kwargs)
148         self._nickname = "{}-{}".format(self.detector, self.observatory[-1])
149         self.plot_settings['cmap'] = 'stereohi{det!s}'.format(det=self.detector[-1])
150         self.plot_settings['norm'] = ImageNormalize(
151             stretch=source_stretch(self.meta, PowerStretch(0.25)), clip=False)
152 
153         # Try to identify when the FITS meta data does not have the correct
154         # date FITS keyword
155         if ('date_obs' in self.meta) and not('date-obs' in self.meta):
156             self.meta['date-obs'] = self.meta['date_obs']
157 
158     @property
159     def measurement(self):
160         """
161         Returns the type of data observed.
162         """
163         # TODO: This needs to do more than white-light.  Should give B, pB, etc.
164         return "white-light"
165 
166     @classmethod
167     def is_datasource_for(cls, data, header, **kwargs):
168         """Determines if header corresponds to an COR image"""
169         return str(header.get('detector', '')).startswith('HI')
170
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/sunpy/map/sources/stereo.py b/sunpy/map/sources/stereo.py
--- a/sunpy/map/sources/stereo.py
+++ b/sunpy/map/sources/stereo.py
@@ -8,6 +8,7 @@
 from astropy.visualization import PowerStretch
 from astropy.visualization.mpl_normalize import ImageNormalize
 
+from sunpy import log
 from sunpy.map import GenericMap
 from sunpy.map.sources.source_type import source_stretch
 
@@ -42,6 +43,10 @@
         # date FITS keyword
         if ('date_obs' in self.meta) and not('date-obs' in self.meta):
             self.meta['date-obs'] = self.meta['date_obs']
+        # fix CROTA to CROTAn
+        if "crota" in self.meta and "crota2" not in self.meta:
+            log.debug("EUVIMap: Changing the CROTA keyword to CROTA2")
+            self.meta["crota2"] = self.meta.pop("crota")
 
     @property
     def rsun_arcseconds(self):

{"golden_diff": "diff --git a/sunpy/map/sources/stereo.py b/sunpy/map/sources/stereo.py\n--- a/sunpy/map/sources/stereo.py\n+++ b/sunpy/map/sources/stereo.py\n@@ -8,6 +8,7 @@\n from astropy.visualization import PowerStretch\n from astropy.visualization.mpl_normalize import ImageNormalize\n \n+from sunpy import log\n from sunpy.map import GenericMap\n from sunpy.map.sources.source_type import source_stretch\n \n@@ -42,6 +43,10 @@\n         # date FITS keyword\n         if ('date_obs' in self.meta) and not('date-obs' in self.meta):\n             self.meta['date-obs'] = self.meta['date_obs']\n+        # fix CROTA to CROTAn\n+        if \"crota\" in self.meta and \"crota2\" not in self.meta:\n+            log.debug(\"EUVIMap: Changing the CROTA keyword to CROTA2\")\n+            self.meta[\"crota2\"] = self.meta.pop(\"crota\")\n \n     @property\n     def rsun_arcseconds(self):\n", "issue": "Fix CROTA in EUVI map source\ne.g. \r\n```python\r\nfrom sunpy.map import Map\r\n\r\nsmap = Map('https://stereo-ssc.nascom.nasa.gov/pub/beacon/ahead/secchi/img/euvi/20210107/20210107_001615_n7euA.fts')\r\nprint(smap.wcs)\r\n```\r\nraises\r\n```\r\nWARNING: FITSFixedWarning: CROTA = -6.39331135705 \r\nkeyword looks very much like CROTAn but isn't. [astropy.wcs.wcs]\r\n```\r\nIt would be good to fix this in the EUVI map source.\n", "before_files": [{"content": "\"\"\"STEREO Map subclass definitions\"\"\"\n\n__author__ = \"Keith Hughitt\"\n__email__ = \"keith.hughitt@nasa.gov\"\n\n\nimport astropy.units as u\nfrom astropy.visualization import PowerStretch\nfrom astropy.visualization.mpl_normalize import ImageNormalize\n\nfrom sunpy.map import GenericMap\nfrom sunpy.map.sources.source_type import source_stretch\n\n__all__ = ['EUVIMap', 'CORMap', 'HIMap']\n\n\nclass EUVIMap(GenericMap):\n    \"\"\"STEREO-SECCHI EUVI Image Map\n\n    EUVI is an extreme ultraviolet (EUV) imager. Part of the STEREO-SECCHI\n    suite it observes the Sun from 1 to 1.7 solar radii. It is capable of\n    observing at 304 (He II), 171 (Fe IX), 195 (Fe XII), and 284 (Fe XV)\n    Angstroms.\n\n    References\n    ----------\n    * `STEREO Mission Page <https://stereo.gsfc.nasa.gov/>`_\n    * `STEREO SECCHI <http://secchi.nrl.navy.mil>`_\n    * `Instrument Page <http://secchi.lmsal.com/EUVI/>`_\n    \"\"\"\n\n    def __init__(self, data, header, **kwargs):\n\n        GenericMap.__init__(self, data, header, **kwargs)\n        self._nickname = \"{}-{}\".format(self.detector, self.observatory[-1])\n        self.plot_settings['cmap'] = 'sohoeit{wl:d}'.format(wl=int(self.wavelength.value))\n        self.plot_settings['norm'] = ImageNormalize(\n            stretch=source_stretch(self.meta, PowerStretch(0.25)), clip=False)\n        self.meta['waveunit'] = 'Angstrom'\n\n        # Try to identify when the FITS meta data does not have the correct\n        # date FITS keyword\n        if ('date_obs' in self.meta) and not('date-obs' in self.meta):\n            self.meta['date-obs'] = self.meta['date_obs']\n\n    @property\n    def rsun_arcseconds(self):\n        \"\"\"\n        Radius of the sun in arcseconds.\n\n        References\n        ----------\n        https://sohowww.nascom.nasa.gov/solarsoft/stereo/secchi/doc/FITS_keywords.pdf\n        \"\"\"\n        return self.meta.get('rsun', None)\n\n    @property\n    def rsun_obs(self):\n        \"\"\"\n        Radius of the sun in arcseconds as a quantity.\n\n        References\n        ----------\n        https://sohowww.nascom.nasa.gov/solarsoft/stereo/secchi/doc/FITS_keywords.pdf\n        \"\"\"\n        rsun_arcseconds = self.meta.get('rsun', None)\n\n        if rsun_arcseconds is None:\n            rsun_arcseconds = super().rsun_obs\n\n        return u.Quantity(rsun_arcseconds, 'arcsec')\n\n    @classmethod\n    def is_datasource_for(cls, data, header, **kwargs):\n        \"\"\"Determines if header corresponds to an EUVI image\"\"\"\n        return header.get('detector') == 'EUVI'\n\n\nclass CORMap(GenericMap):\n    \"\"\"STEREO-SECCHI CORonograph Image Map.\n\n    Part of the STEREO-SECCHI suite of remote sensing telescopes,\n    COR is a set of two coronographs (COR1, COR2) onboard STEREO.\n    They are both traditional Lyot coronagraphs.\n\n    The COR1 detectors observes from 1.3 to 4 solar radii while the\n    COR2 detectors observe a range from 2 to 15 solar radii.\n\n    References\n    ----------\n    * `STEREO Mission Page <https://stereo.gsfc.nasa.gov/>`_\n    * `STEREO SECCHI <http://secchi.nrl.navy.mil>`_\n    * `COR1 Instrument Page <https://cor1.gsfc.nasa.gov>`_\n    * `COR2 Instrument Page <http://secchi.nrl.navy.mil/index.php?p=cor2>`_\n    * `COR1 User Guide <https://cor1.gsfc.nasa.gov/guide/>`_\n    \"\"\"\n\n    def __init__(self, data, header, **kwargs):\n\n        GenericMap.__init__(self, data, header, **kwargs)\n\n        self._nickname = \"{}-{}\".format(self.detector, self.observatory[-1])\n        self.plot_settings['cmap'] = 'stereocor{det!s}'.format(det=self.detector[-1])\n        self.plot_settings['norm'] = ImageNormalize(\n            stretch=source_stretch(self.meta, PowerStretch(0.5)), clip=False)\n\n        # Try to identify when the FITS meta data does not have the correct\n        # date FITS keyword\n        if ('date_obs' in self.meta) and not('date-obs' in self.meta):\n            self.meta['date-obs'] = self.meta['date_obs']\n\n    @property\n    def measurement(self):\n        \"\"\"\n        Returns the type of data observed.\n        \"\"\"\n        # TODO: This needs to do more than white-light.  Should give B, pB, etc.\n        return \"white-light\"\n\n    @classmethod\n    def is_datasource_for(cls, data, header, **kwargs):\n        \"\"\"Determines if header corresponds to an COR image\"\"\"\n        return str(header.get('detector', '')).startswith('COR')\n\n\nclass HIMap(GenericMap):\n    \"\"\"STEREO-SECCHI Heliospheric Imager (HI) Map.\n\n    The HI is a wide-angle visible-light imaging system\n    for the detection of coronal mass ejection (CME) events\n    in interplanetary space and, in particular, of events\n    directed towards the Earth.\n\n    The Heliospheric imager consists of two instruments, the HI-1 and HI-2.\n    The HI1 observes from 15-80 solar radii while HI2 observes from 80-215\n    solar radii.\n\n    References\n    ----------\n    * `STEREO Mission Page <https://stereo.gsfc.nasa.gov/>`_\n    * `STEREO SECCHI <https://secchi.nrl.navy.mil>`_\n    * `HI Instrument Page <http://www.stereo.rl.ac.uk>`_\n    \"\"\"\n\n    def __init__(self, data, header, **kwargs):\n\n        GenericMap.__init__(self, data, header, **kwargs)\n        self._nickname = \"{}-{}\".format(self.detector, self.observatory[-1])\n        self.plot_settings['cmap'] = 'stereohi{det!s}'.format(det=self.detector[-1])\n        self.plot_settings['norm'] = ImageNormalize(\n            stretch=source_stretch(self.meta, PowerStretch(0.25)), clip=False)\n\n        # Try to identify when the FITS meta data does not have the correct\n        # date FITS keyword\n        if ('date_obs' in self.meta) and not('date-obs' in self.meta):\n            self.meta['date-obs'] = self.meta['date_obs']\n\n    @property\n    def measurement(self):\n        \"\"\"\n        Returns the type of data observed.\n        \"\"\"\n        # TODO: This needs to do more than white-light.  Should give B, pB, etc.\n        return \"white-light\"\n\n    @classmethod\n    def is_datasource_for(cls, data, header, **kwargs):\n        \"\"\"Determines if header corresponds to an COR image\"\"\"\n        return str(header.get('detector', '')).startswith('HI')\n", "path": "sunpy/map/sources/stereo.py"}], "after_files": [{"content": "\"\"\"STEREO Map subclass definitions\"\"\"\n\n__author__ = \"Keith Hughitt\"\n__email__ = \"keith.hughitt@nasa.gov\"\n\n\nimport astropy.units as u\nfrom astropy.visualization import PowerStretch\nfrom astropy.visualization.mpl_normalize import ImageNormalize\n\nfrom sunpy import log\nfrom sunpy.map import GenericMap\nfrom sunpy.map.sources.source_type import source_stretch\n\n__all__ = ['EUVIMap', 'CORMap', 'HIMap']\n\n\nclass EUVIMap(GenericMap):\n    \"\"\"STEREO-SECCHI EUVI Image Map\n\n    EUVI is an extreme ultraviolet (EUV) imager. Part of the STEREO-SECCHI\n    suite it observes the Sun from 1 to 1.7 solar radii. It is capable of\n    observing at 304 (He II), 171 (Fe IX), 195 (Fe XII), and 284 (Fe XV)\n    Angstroms.\n\n    References\n    ----------\n    * `STEREO Mission Page <https://stereo.gsfc.nasa.gov/>`_\n    * `STEREO SECCHI <http://secchi.nrl.navy.mil>`_\n    * `Instrument Page <http://secchi.lmsal.com/EUVI/>`_\n    \"\"\"\n\n    def __init__(self, data, header, **kwargs):\n\n        GenericMap.__init__(self, data, header, **kwargs)\n        self._nickname = \"{}-{}\".format(self.detector, self.observatory[-1])\n        self.plot_settings['cmap'] = 'sohoeit{wl:d}'.format(wl=int(self.wavelength.value))\n        self.plot_settings['norm'] = ImageNormalize(\n            stretch=source_stretch(self.meta, PowerStretch(0.25)), clip=False)\n        self.meta['waveunit'] = 'Angstrom'\n\n        # Try to identify when the FITS meta data does not have the correct\n        # date FITS keyword\n        if ('date_obs' in self.meta) and not('date-obs' in self.meta):\n            self.meta['date-obs'] = self.meta['date_obs']\n        # fix CROTA to CROTAn\n        if \"crota\" in self.meta and \"crota2\" not in self.meta:\n            log.debug(\"EUVIMap: Changing the CROTA keyword to CROTA2\")\n            self.meta[\"crota2\"] = self.meta.pop(\"crota\")\n\n    @property\n    def rsun_arcseconds(self):\n        \"\"\"\n        Radius of the sun in arcseconds.\n\n        References\n        ----------\n        https://sohowww.nascom.nasa.gov/solarsoft/stereo/secchi/doc/FITS_keywords.pdf\n        \"\"\"\n        return self.meta.get('rsun', None)\n\n    @property\n    def rsun_obs(self):\n        \"\"\"\n        Radius of the sun in arcseconds as a quantity.\n\n        References\n        ----------\n        https://sohowww.nascom.nasa.gov/solarsoft/stereo/secchi/doc/FITS_keywords.pdf\n        \"\"\"\n        rsun_arcseconds = self.meta.get('rsun', None)\n\n        if rsun_arcseconds is None:\n            rsun_arcseconds = super().rsun_obs\n\n        return u.Quantity(rsun_arcseconds, 'arcsec')\n\n    @classmethod\n    def is_datasource_for(cls, data, header, **kwargs):\n        \"\"\"Determines if header corresponds to an EUVI image\"\"\"\n        return header.get('detector') == 'EUVI'\n\n\nclass CORMap(GenericMap):\n    \"\"\"STEREO-SECCHI CORonograph Image Map.\n\n    Part of the STEREO-SECCHI suite of remote sensing telescopes,\n    COR is a set of two coronographs (COR1, COR2) onboard STEREO.\n    They are both traditional Lyot coronagraphs.\n\n    The COR1 detectors observes from 1.3 to 4 solar radii while the\n    COR2 detectors observe a range from 2 to 15 solar radii.\n\n    References\n    ----------\n    * `STEREO Mission Page <https://stereo.gsfc.nasa.gov/>`_\n    * `STEREO SECCHI <http://secchi.nrl.navy.mil>`_\n    * `COR1 Instrument Page <https://cor1.gsfc.nasa.gov>`_\n    * `COR2 Instrument Page <http://secchi.nrl.navy.mil/index.php?p=cor2>`_\n    * `COR1 User Guide <https://cor1.gsfc.nasa.gov/guide/>`_\n    \"\"\"\n\n    def __init__(self, data, header, **kwargs):\n\n        GenericMap.__init__(self, data, header, **kwargs)\n\n        self._nickname = \"{}-{}\".format(self.detector, self.observatory[-1])\n        self.plot_settings['cmap'] = 'stereocor{det!s}'.format(det=self.detector[-1])\n        self.plot_settings['norm'] = ImageNormalize(\n            stretch=source_stretch(self.meta, PowerStretch(0.5)), clip=False)\n\n        # Try to identify when the FITS meta data does not have the correct\n        # date FITS keyword\n        if ('date_obs' in self.meta) and not('date-obs' in self.meta):\n            self.meta['date-obs'] = self.meta['date_obs']\n\n    @property\n    def measurement(self):\n        \"\"\"\n        Returns the type of data observed.\n        \"\"\"\n        # TODO: This needs to do more than white-light.  Should give B, pB, etc.\n        return \"white-light\"\n\n    @classmethod\n    def is_datasource_for(cls, data, header, **kwargs):\n        \"\"\"Determines if header corresponds to an COR image\"\"\"\n        return str(header.get('detector', '')).startswith('COR')\n\n\nclass HIMap(GenericMap):\n    \"\"\"STEREO-SECCHI Heliospheric Imager (HI) Map.\n\n    The HI is a wide-angle visible-light imaging system\n    for the detection of coronal mass ejection (CME) events\n    in interplanetary space and, in particular, of events\n    directed towards the Earth.\n\n    The Heliospheric imager consists of two instruments, the HI-1 and HI-2.\n    The HI1 observes from 15-80 solar radii while HI2 observes from 80-215\n    solar radii.\n\n    References\n    ----------\n    * `STEREO Mission Page <https://stereo.gsfc.nasa.gov/>`_\n    * `STEREO SECCHI <https://secchi.nrl.navy.mil>`_\n    * `HI Instrument Page <http://www.stereo.rl.ac.uk>`_\n    \"\"\"\n\n    def __init__(self, data, header, **kwargs):\n\n        GenericMap.__init__(self, data, header, **kwargs)\n        self._nickname = \"{}-{}\".format(self.detector, self.observatory[-1])\n        self.plot_settings['cmap'] = 'stereohi{det!s}'.format(det=self.detector[-1])\n        self.plot_settings['norm'] = ImageNormalize(\n            stretch=source_stretch(self.meta, PowerStretch(0.25)), clip=False)\n\n        # Try to identify when the FITS meta data does not have the correct\n        # date FITS keyword\n        if ('date_obs' in self.meta) and not('date-obs' in self.meta):\n            self.meta['date-obs'] = self.meta['date_obs']\n\n    @property\n    def measurement(self):\n        \"\"\"\n        Returns the type of data observed.\n        \"\"\"\n        # TODO: This needs to do more than white-light.  Should give B, pB, etc.\n        return \"white-light\"\n\n    @classmethod\n    def is_datasource_for(cls, data, header, **kwargs):\n        \"\"\"Determines if header corresponds to an COR image\"\"\"\n        return str(header.get('detector', '')).startswith('HI')\n", "path": "sunpy/map/sources/stereo.py"}]}