TYPING: change to FrameOrSeries Alias in pandas._typing (#28173)

Author: simonjayhawkins

pandas/_typing.py

@@ -11,9 +11,9 @@
  from pandas.core.arrays.base import ExtensionArray # noqa: F401
  from pandas.core.dtypes.dtypes import ExtensionDtype # noqa: F401
  from pandas.core.indexes.base import Index # noqa: F401
- from pandas.core.frame import DataFrame # noqa: F401
  from pandas.core.series import Series # noqa: F401
  from pandas.core.sparse.series import SparseSeries # noqa: F401
+ from pandas.core.generic import NDFrame # noqa: F401
 
 
 AnyArrayLike = TypeVar(
@@ -24,7 +24,10 @@
 Dtype = Union[str, np.dtype, "ExtensionDtype"]
 FilePathOrBuffer = Union[str, Path, IO[AnyStr]]
 
-FrameOrSeries = TypeVar("FrameOrSeries", "Series", "DataFrame")
+FrameOrSeries = TypeVar("FrameOrSeries", bound="NDFrame")
 Scalar = Union[str, int, float]
 Axis = Union[str, int]
 Ordered = Optional[bool]
+
+# to maintain type information across generic functions and parametrization
+_T = TypeVar("_T")