We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
bug: isolated dask backend tests fail due to removed imports
For some reason lines 6 and 8 here: https://github.com/ibis-project/ibis/commit/a1262410310bb4d638a73e1cdfbe93c2b4089905#diff-96d84d9b6e9e84a2be7a046dc9853df1ca5fc6e894307339b02cd61e666c0149L6-L8

were removed.

This causes dasks tests to fail when they are run in isolation from other tests that (transitively) import from the pandas backend.

This is both a ci bug and a bug in the code, since we're not testing backends independently. Perhaps unsurprisingly I discovered the bug in #2937, which fixes the CI part of this problem.

--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `ibis/backends/dask/__init__.py`
Content:
```
1 from typing import Mapping
2 
3 import dask
4 import dask.dataframe as dd
5 import pandas as pd
6 import toolz
7 from dask.base import DaskMethodsMixin
8 
9 import ibis.common.exceptions as com
10 import ibis.config
11 import ibis.expr.schema as sch
12 import ibis.expr.types as ir
13 from ibis.backends.pandas import BasePandasBackend
14 
15 from .client import DaskDatabase, DaskTable, ibis_schema_to_dask
16 from .core import execute_and_reset
17 
18 # Make sure that the pandas backend is loaded, dispatching has been
19 # executed, and options have been loaded
20 ibis.pandas
21 
22 
23 class Backend(BasePandasBackend):
24     name = 'dask'
25     database_class = DaskDatabase
26     table_class = DaskTable
27 
28     def connect(self, dictionary):
29         # register dispatchers
30         from . import udf  # noqa: F401
31 
32         return super().connect(dictionary)
33 
34     @property
35     def version(self):
36         return dask.__version__
37 
38     def execute(
39         self,
40         query: ir.Expr,
41         params: Mapping[ir.Expr, object] = None,
42         limit: str = 'default',
43         **kwargs,
44     ):
45         if limit != 'default':
46             raise ValueError(
47                 'limit parameter to execute is not yet implemented in the '
48                 'dask backend'
49             )
50 
51         if not isinstance(query, ir.Expr):
52             raise TypeError(
53                 "`query` has type {!r}, expected ibis.expr.types.Expr".format(
54                     type(query).__name__
55                 )
56             )
57 
58         result = self.compile(query, params, **kwargs)
59         if isinstance(result, DaskMethodsMixin):
60             return result.compute()
61         else:
62             return result
63 
64     def compile(
65         self, query: ir.Expr, params: Mapping[ir.Expr, object] = None, **kwargs
66     ):
67         """Compile `expr`.
68 
69         Notes
70         -----
71         For the dask backend returns a dask graph that you can run ``.compute``
72         on to get a pandas object.
73 
74         """
75         return execute_and_reset(query, params=params, **kwargs)
76 
77     def create_table(
78         self,
79         table_name: str,
80         obj: dd.DataFrame = None,
81         schema: sch.Schema = None,
82     ):
83         """Create a table."""
84         if obj is not None:
85             df = obj
86         elif schema is not None:
87             dtypes = ibis_schema_to_dask(schema)
88             df = schema.apply_to(
89                 dd.from_pandas(
90                     pd.DataFrame(columns=list(map(toolz.first, dtypes))),
91                     npartitions=1,
92                 )
93             )
94         else:
95             raise com.IbisError('Must pass expr or schema')
96 
97         self.dictionary[table_name] = df
98
```
--- 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/ibis/backends/dask/__init__.py b/ibis/backends/dask/__init__.py
--- a/ibis/backends/dask/__init__.py
+++ b/ibis/backends/dask/__init__.py
@@ -6,6 +6,9 @@
 import toolz
 from dask.base import DaskMethodsMixin
 
+# import the pandas execution module to register dispatched implementations of
+# execute_node that the dask backend will later override
+import ibis.backends.pandas.execution  # noqa: F401
 import ibis.common.exceptions as com
 import ibis.config
 import ibis.expr.schema as sch
@@ -15,8 +18,7 @@
 from .client import DaskDatabase, DaskTable, ibis_schema_to_dask
 from .core import execute_and_reset
 
-# Make sure that the pandas backend is loaded, dispatching has been
-# executed, and options have been loaded
+# Make sure that the pandas backend options have been loaded
 ibis.pandas

{"golden_diff": "diff --git a/ibis/backends/dask/__init__.py b/ibis/backends/dask/__init__.py\n--- a/ibis/backends/dask/__init__.py\n+++ b/ibis/backends/dask/__init__.py\n@@ -6,6 +6,9 @@\n import toolz\n from dask.base import DaskMethodsMixin\n \n+# import the pandas execution module to register dispatched implementations of\n+# execute_node that the dask backend will later override\n+import ibis.backends.pandas.execution  # noqa: F401\n import ibis.common.exceptions as com\n import ibis.config\n import ibis.expr.schema as sch\n@@ -15,8 +18,7 @@\n from .client import DaskDatabase, DaskTable, ibis_schema_to_dask\n from .core import execute_and_reset\n \n-# Make sure that the pandas backend is loaded, dispatching has been\n-# executed, and options have been loaded\n+# Make sure that the pandas backend options have been loaded\n ibis.pandas\n", "issue": "bug: isolated dask backend tests fail due to removed imports\nFor some reason lines 6 and 8 here: https://github.com/ibis-project/ibis/commit/a1262410310bb4d638a73e1cdfbe93c2b4089905#diff-96d84d9b6e9e84a2be7a046dc9853df1ca5fc6e894307339b02cd61e666c0149L6-L8\r\n\r\nwere removed.\r\n\r\nThis causes dasks tests to fail when they are run in isolation from other tests that (transitively) import from the pandas backend.\r\n\r\nThis is both a ci bug and a bug in the code, since we're not testing backends independently. Perhaps unsurprisingly I discovered the bug in #2937, which fixes the CI part of this problem.\n", "before_files": [{"content": "from typing import Mapping\n\nimport dask\nimport dask.dataframe as dd\nimport pandas as pd\nimport toolz\nfrom dask.base import DaskMethodsMixin\n\nimport ibis.common.exceptions as com\nimport ibis.config\nimport ibis.expr.schema as sch\nimport ibis.expr.types as ir\nfrom ibis.backends.pandas import BasePandasBackend\n\nfrom .client import DaskDatabase, DaskTable, ibis_schema_to_dask\nfrom .core import execute_and_reset\n\n# Make sure that the pandas backend is loaded, dispatching has been\n# executed, and options have been loaded\nibis.pandas\n\n\nclass Backend(BasePandasBackend):\n    name = 'dask'\n    database_class = DaskDatabase\n    table_class = DaskTable\n\n    def connect(self, dictionary):\n        # register dispatchers\n        from . import udf  # noqa: F401\n\n        return super().connect(dictionary)\n\n    @property\n    def version(self):\n        return dask.__version__\n\n    def execute(\n        self,\n        query: ir.Expr,\n        params: Mapping[ir.Expr, object] = None,\n        limit: str = 'default',\n        **kwargs,\n    ):\n        if limit != 'default':\n            raise ValueError(\n                'limit parameter to execute is not yet implemented in the '\n                'dask backend'\n            )\n\n        if not isinstance(query, ir.Expr):\n            raise TypeError(\n                \"`query` has type {!r}, expected ibis.expr.types.Expr\".format(\n                    type(query).__name__\n                )\n            )\n\n        result = self.compile(query, params, **kwargs)\n        if isinstance(result, DaskMethodsMixin):\n            return result.compute()\n        else:\n            return result\n\n    def compile(\n        self, query: ir.Expr, params: Mapping[ir.Expr, object] = None, **kwargs\n    ):\n        \"\"\"Compile `expr`.\n\n        Notes\n        -----\n        For the dask backend returns a dask graph that you can run ``.compute``\n        on to get a pandas object.\n\n        \"\"\"\n        return execute_and_reset(query, params=params, **kwargs)\n\n    def create_table(\n        self,\n        table_name: str,\n        obj: dd.DataFrame = None,\n        schema: sch.Schema = None,\n    ):\n        \"\"\"Create a table.\"\"\"\n        if obj is not None:\n            df = obj\n        elif schema is not None:\n            dtypes = ibis_schema_to_dask(schema)\n            df = schema.apply_to(\n                dd.from_pandas(\n                    pd.DataFrame(columns=list(map(toolz.first, dtypes))),\n                    npartitions=1,\n                )\n            )\n        else:\n            raise com.IbisError('Must pass expr or schema')\n\n        self.dictionary[table_name] = df\n", "path": "ibis/backends/dask/__init__.py"}], "after_files": [{"content": "from typing import Mapping\n\nimport dask\nimport dask.dataframe as dd\nimport pandas as pd\nimport toolz\nfrom dask.base import DaskMethodsMixin\n\n# import the pandas execution module to register dispatched implementations of\n# execute_node that the dask backend will later override\nimport ibis.backends.pandas.execution  # noqa: F401\nimport ibis.common.exceptions as com\nimport ibis.config\nimport ibis.expr.schema as sch\nimport ibis.expr.types as ir\nfrom ibis.backends.pandas import BasePandasBackend\n\nfrom .client import DaskDatabase, DaskTable, ibis_schema_to_dask\nfrom .core import execute_and_reset\n\n# Make sure that the pandas backend options have been loaded\nibis.pandas\n\n\nclass Backend(BasePandasBackend):\n    name = 'dask'\n    database_class = DaskDatabase\n    table_class = DaskTable\n\n    def connect(self, dictionary):\n        # register dispatchers\n        from . import udf  # noqa: F401\n\n        return super().connect(dictionary)\n\n    @property\n    def version(self):\n        return dask.__version__\n\n    def execute(\n        self,\n        query: ir.Expr,\n        params: Mapping[ir.Expr, object] = None,\n        limit: str = 'default',\n        **kwargs,\n    ):\n        if limit != 'default':\n            raise ValueError(\n                'limit parameter to execute is not yet implemented in the '\n                'dask backend'\n            )\n\n        if not isinstance(query, ir.Expr):\n            raise TypeError(\n                \"`query` has type {!r}, expected ibis.expr.types.Expr\".format(\n                    type(query).__name__\n                )\n            )\n\n        result = self.compile(query, params, **kwargs)\n        if isinstance(result, DaskMethodsMixin):\n            return result.compute()\n        else:\n            return result\n\n    def compile(\n        self, query: ir.Expr, params: Mapping[ir.Expr, object] = None, **kwargs\n    ):\n        \"\"\"Compile `expr`.\n\n        Notes\n        -----\n        For the dask backend returns a dask graph that you can run ``.compute``\n        on to get a pandas object.\n\n        \"\"\"\n        return execute_and_reset(query, params=params, **kwargs)\n\n    def create_table(\n        self,\n        table_name: str,\n        obj: dd.DataFrame = None,\n        schema: sch.Schema = None,\n    ):\n        \"\"\"Create a table.\"\"\"\n        if obj is not None:\n            df = obj\n        elif schema is not None:\n            dtypes = ibis_schema_to_dask(schema)\n            df = schema.apply_to(\n                dd.from_pandas(\n                    pd.DataFrame(columns=list(map(toolz.first, dtypes))),\n                    npartitions=1,\n                )\n            )\n        else:\n            raise com.IbisError('Must pass expr or schema')\n\n        self.dictionary[table_name] = df\n", "path": "ibis/backends/dask/__init__.py"}]}