We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
HistogramLUTWidget kargs bug?
# lut_widget = HistogramLUTWidget(background='w')

 File "/usr/local/lib/python3.4/dist-packages/pyqtgraph-0.9.8-py3.4.egg/pyqtgraph/widgets/HistogramLUTWidget.py", line 18, in **init**
    self.item = HistogramLUTItem(_args, *_kargs)
# TypeError: **init**() got an unexpected keyword argument 'background'

I can fix it by:

class HistogramLUTWidget(pg.GraphicsView):

```
def __init__(self, parent=None,  *args, **kargs):
    # background = kargs.get('background', 'default')
    background = kargs.pop('background', 'default')
```

...


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `pyqtgraph/widgets/HistogramLUTWidget.py`
Content:
```
1 """
2 Widget displaying an image histogram along with gradient editor. Can be used to adjust the appearance of images.
3 This is a wrapper around HistogramLUTItem
4 """
5 
6 from ..Qt import QtGui, QtCore
7 from .GraphicsView import GraphicsView
8 from ..graphicsItems.HistogramLUTItem import HistogramLUTItem
9 
10 __all__ = ['HistogramLUTWidget']
11 
12 
13 class HistogramLUTWidget(GraphicsView):
14     
15     def __init__(self, parent=None,  *args, **kargs):
16         background = kargs.get('background', 'default')
17         GraphicsView.__init__(self, parent, useOpenGL=False, background=background)
18         self.item = HistogramLUTItem(*args, **kargs)
19         self.setCentralItem(self.item)
20         self.setSizePolicy(QtGui.QSizePolicy.Preferred, QtGui.QSizePolicy.Expanding)
21         self.setMinimumWidth(95)
22         
23 
24     def sizeHint(self):
25         return QtCore.QSize(115, 200)
26     
27     
28 
29     def __getattr__(self, attr):
30         return getattr(self.item, attr)
31 
32 
33 
34
```
--- 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/pyqtgraph/widgets/HistogramLUTWidget.py b/pyqtgraph/widgets/HistogramLUTWidget.py
--- a/pyqtgraph/widgets/HistogramLUTWidget.py
+++ b/pyqtgraph/widgets/HistogramLUTWidget.py
@@ -13,7 +13,7 @@
 class HistogramLUTWidget(GraphicsView):
     
     def __init__(self, parent=None,  *args, **kargs):
-        background = kargs.get('background', 'default')
+        background = kargs.pop('background', 'default')
         GraphicsView.__init__(self, parent, useOpenGL=False, background=background)
         self.item = HistogramLUTItem(*args, **kargs)
         self.setCentralItem(self.item)

{"golden_diff": "diff --git a/pyqtgraph/widgets/HistogramLUTWidget.py b/pyqtgraph/widgets/HistogramLUTWidget.py\n--- a/pyqtgraph/widgets/HistogramLUTWidget.py\n+++ b/pyqtgraph/widgets/HistogramLUTWidget.py\n@@ -13,7 +13,7 @@\n class HistogramLUTWidget(GraphicsView):\n     \n     def __init__(self, parent=None,  *args, **kargs):\n-        background = kargs.get('background', 'default')\n+        background = kargs.pop('background', 'default')\n         GraphicsView.__init__(self, parent, useOpenGL=False, background=background)\n         self.item = HistogramLUTItem(*args, **kargs)\n         self.setCentralItem(self.item)\n", "issue": "HistogramLUTWidget kargs bug?\n# lut_widget = HistogramLUTWidget(background='w')\n\n File \"/usr/local/lib/python3.4/dist-packages/pyqtgraph-0.9.8-py3.4.egg/pyqtgraph/widgets/HistogramLUTWidget.py\", line 18, in **init**\n    self.item = HistogramLUTItem(_args, *_kargs)\n# TypeError: **init**() got an unexpected keyword argument 'background'\n\nI can fix it by:\n\nclass HistogramLUTWidget(pg.GraphicsView):\n\n```\ndef __init__(self, parent=None,  *args, **kargs):\n    # background = kargs.get('background', 'default')\n    background = kargs.pop('background', 'default')\n```\n\n...\n\n", "before_files": [{"content": "\"\"\"\nWidget displaying an image histogram along with gradient editor. Can be used to adjust the appearance of images.\nThis is a wrapper around HistogramLUTItem\n\"\"\"\n\nfrom ..Qt import QtGui, QtCore\nfrom .GraphicsView import GraphicsView\nfrom ..graphicsItems.HistogramLUTItem import HistogramLUTItem\n\n__all__ = ['HistogramLUTWidget']\n\n\nclass HistogramLUTWidget(GraphicsView):\n    \n    def __init__(self, parent=None,  *args, **kargs):\n        background = kargs.get('background', 'default')\n        GraphicsView.__init__(self, parent, useOpenGL=False, background=background)\n        self.item = HistogramLUTItem(*args, **kargs)\n        self.setCentralItem(self.item)\n        self.setSizePolicy(QtGui.QSizePolicy.Preferred, QtGui.QSizePolicy.Expanding)\n        self.setMinimumWidth(95)\n        \n\n    def sizeHint(self):\n        return QtCore.QSize(115, 200)\n    \n    \n\n    def __getattr__(self, attr):\n        return getattr(self.item, attr)\n\n\n\n", "path": "pyqtgraph/widgets/HistogramLUTWidget.py"}], "after_files": [{"content": "\"\"\"\nWidget displaying an image histogram along with gradient editor. Can be used to adjust the appearance of images.\nThis is a wrapper around HistogramLUTItem\n\"\"\"\n\nfrom ..Qt import QtGui, QtCore\nfrom .GraphicsView import GraphicsView\nfrom ..graphicsItems.HistogramLUTItem import HistogramLUTItem\n\n__all__ = ['HistogramLUTWidget']\n\n\nclass HistogramLUTWidget(GraphicsView):\n    \n    def __init__(self, parent=None,  *args, **kargs):\n        background = kargs.pop('background', 'default')\n        GraphicsView.__init__(self, parent, useOpenGL=False, background=background)\n        self.item = HistogramLUTItem(*args, **kargs)\n        self.setCentralItem(self.item)\n        self.setSizePolicy(QtGui.QSizePolicy.Preferred, QtGui.QSizePolicy.Expanding)\n        self.setMinimumWidth(95)\n        \n\n    def sizeHint(self):\n        return QtCore.QSize(115, 200)\n    \n    \n\n    def __getattr__(self, attr):\n        return getattr(self.item, attr)\n\n\n\n", "path": "pyqtgraph/widgets/HistogramLUTWidget.py"}]}