change cast to dtype="datetime64[ns]"

Author: arthurlw

pandas/core/arrays/arrow/array.py

@@ -1484,7 +1484,7 @@ def map(self, mapper, na_action: Literal["ignore"] | None = None):
         if is_numeric_dtype(self.dtype):
             return map_array(self.to_numpy(), mapper, na_action=na_action)
         elif self.dtype == "timestamp[ns][pyarrow]":
-            return map_array(self.to_numpy(dtype=object), mapper, na_action=na_action)
+            return map_array(self.to_numpy(dtype="datetime64[ns]"), mapper, na_action=na_action)
         else:
             return super().map(mapper, na_action)