CLN: various lgtm.com cleanups (#30258)

Author: simonjayhawkins

pandas/core/apply.py

@@ -320,7 +320,6 @@ def apply_series_generator(self) -> Tuple[ResType, "Index"]:
         series_gen = self.series_generator
         res_index = self.result_index
 
-        i = None
         keys = []
         results = {}
         if self.ignore_failures:

pandas/core/arrays/datetimes.py

@@ -2109,7 +2109,6 @@ def _validate_dt64_dtype(dtype):
         dtype = pandas_dtype(dtype)
         if is_dtype_equal(dtype, np.dtype("M8")):
             # no precision, disallowed GH#24806
-            dtype = _NS_DTYPE
             msg = (
                 "Passing in 'datetime64' dtype with no precision is not allowed. "
                 "Please pass in 'datetime64[ns]' instead."

pandas/core/arrays/integer.py

@@ -78,7 +78,8 @@ def itemsize(self):
 
     @classmethod
     def construct_array_type(cls):
-        """Return the array type associated with this dtype
+        """
+        Return the array type associated with this dtype.
 
         Returns
         -------

pandas/core/arrays/numpy_.py

@@ -79,7 +79,15 @@ def construct_from_string(cls, string):
                 f"Cannot construct a 'PandasDtype' from '{string}'"
             ) from err
 
+    @classmethod
     def construct_array_type(cls):
+        """
+        Return the array type associated with this dtype.
+
+        Returns
+        -------
+        type
+        """
         return PandasArray
 
     @property

pandas/core/arrays/sparse/dtype.py

@@ -168,6 +168,13 @@ def __repr__(self) -> str:
 
     @classmethod
     def construct_array_type(cls):
+        """
+        Return the array type associated with this dtype.
+
+        Returns
+        -------
+        type
+        """
         from .array import SparseArray
 
         return SparseArray

pandas/core/arrays/timedeltas.py

@@ -1122,7 +1122,6 @@ def _validate_td64_dtype(dtype):
     dtype = pandas_dtype(dtype)
     if is_dtype_equal(dtype, np.dtype("timedelta64")):
         # no precision disallowed GH#24806
-        dtype = _TD_DTYPE
         msg = (
             "Passing in 'timedelta' dtype with no precision is not allowed. "
             "Please pass in 'timedelta64[ns]' instead."

pandas/core/dtypes/base.py

@@ -183,7 +183,7 @@ def names(self) -> Optional[List[str]]:
     @classmethod
     def construct_array_type(cls):
         """
-        Return the array type associated with this dtype
+        Return the array type associated with this dtype.
 
         Returns
         -------

pandas/core/dtypes/dtypes.py

@@ -486,7 +486,7 @@ def _hash_categories(categories, ordered: Ordered = True) -> int:
     @classmethod
     def construct_array_type(cls):
         """
-        Return the array type associated with this dtype
+        Return the array type associated with this dtype.
 
         Returns
         -------
@@ -668,7 +668,7 @@ def __init__(self, unit="ns", tz=None):
                 unit = result.unit
                 tz = result.tz
                 msg = (
-                    "Passing a dtype alias like 'datetime64[ns, {tz}]' "
+                    f"Passing a dtype alias like 'datetime64[ns, {tz}]' "
                     "to DatetimeTZDtype is no longer supported. Use "
                     "'DatetimeTZDtype.construct_from_string()' instead."
                 )
@@ -704,7 +704,7 @@ def tz(self):
     @classmethod
     def construct_array_type(cls):
         """
-        Return the array type associated with this dtype
+        Return the array type associated with this dtype.
 
         Returns
         -------
@@ -936,6 +936,13 @@ def is_dtype(cls, dtype) -> bool:
 
     @classmethod
     def construct_array_type(cls):
+        """
+        Return the array type associated with this dtype.
+
+        Returns
+        -------
+        type
+        """
         from pandas.core.arrays import PeriodArray
 
         return PeriodArray
@@ -1030,7 +1037,7 @@ def subtype(self):
     @classmethod
     def construct_array_type(cls):
         """
-        Return the array type associated with this dtype
+        Return the array type associated with this dtype.
 
         Returns
         -------

pandas/core/frame.py

@@ -2587,7 +2587,6 @@ def _ixs(self, i: int, axis: int = 0):
         """
         # irow
         if axis == 0:
-            label = self.index[i]
             new_values = self._data.fast_xs(i)
 
             # if we are a copy, mark as such

pandas/core/generic.py

@@ -5746,8 +5746,6 @@ def __deepcopy__(self: FrameOrSeries, memo=None) -> FrameOrSeries:
         memo, default None
             Standard signature. Unused
         """
-        if memo is None:
-            memo = {}
         return self.copy(deep=True)
 
     def _convert(