add allow slice to is_hashable

Author: LirongMa

pandas/core/dtypes/inference.py

@@ -376,7 +376,7 @@ def is_named_tuple(obj: object) -> bool:
     return isinstance(obj, abc.Sequence) and hasattr(obj, "_fields")
 
 
-def is_hashable(obj: object) -> TypeGuard[Hashable]:
+def is_hashable(obj: object, allow_slice: bool=None) -> TypeGuard[Hashable]:
     """
     Return True if hash(obj) will succeed, False otherwise.
 
@@ -390,13 +390,17 @@ def is_hashable(obj: object) -> TypeGuard[Hashable]:
     ----------
     obj : object
         The object to check for hashability. Any Python object can be passed here.
+    allow_slice: bool or None
+        - If True: return True if the object is hashable (including slices).
+        - If False: return True if the object is hashable and not a slice.
+        - If None: return True of the object is hashable. without checking for slice type.
 
     Returns
     -------
     bool
         True if object can be hashed (i.e., does not raise TypeError when
-        passed to hash()), and False otherwise (e.g., if object is mutable
-        like a list or dictionary).
+        passed to hash()) and allow_slice is True or None, and False otherwise
+        (e.g., if object is mutable like a list or dictionary).
 
     See Also
     --------
@@ -427,6 +431,8 @@ def is_hashable(obj: object) -> TypeGuard[Hashable]:
     except TypeError:
         return False
     else:
+        if allow_slice is False and isinstance(obj, slice):
+            return False
         return True