CLN: Remove unused private code in sas module (#57819)

Remove unused private code in sas module

Author: tqa236

pandas/io/sas/sas7bdat.py

@@ -17,10 +17,7 @@
 from __future__ import annotations
 
 from collections import abc
-from datetime import (
-    datetime,
-    timedelta,
-)
+from datetime import datetime
 import sys
 from typing import TYPE_CHECKING
 
@@ -44,7 +41,6 @@
 from pandas import (
     DataFrame,
     Timestamp,
-    isna,
 )
 
 from pandas.io.common import get_handle
@@ -55,7 +51,6 @@
     from pandas._typing import (
         CompressionOptions,
         FilePath,
-        NaTType,
         ReadBuffer,
     )
 
@@ -64,20 +59,6 @@
 _sas_origin = Timestamp("1960-01-01")
 
 
-def _parse_datetime(sas_datetime: float, unit: str) -> datetime | NaTType:
-    if isna(sas_datetime):
-        return pd.NaT
-
-    if unit == "s":
-        return datetime(1960, 1, 1) + timedelta(seconds=sas_datetime)
-
-    elif unit == "d":
-        return datetime(1960, 1, 1) + timedelta(days=sas_datetime)
-
-    else:
-        raise ValueError("unit must be 'd' or 's'")
-
-
 def _convert_datetimes(sas_datetimes: pd.Series, unit: str) -> pd.Series:
     """
     Convert to Timestamp if possible, otherwise to datetime.datetime.
@@ -370,11 +351,6 @@ def _read_bytes(self, offset: int, length: int):
             raise ValueError("The cached page is too small.")
         return self._cached_page[offset : offset + length]
 
-    def _read_and_convert_header_text(self, offset: int, length: int) -> str | bytes:
-        return self._convert_header_text(
-            self._read_bytes(offset, length).rstrip(b"\x00 ")
-        )
-
     def _parse_metadata(self) -> None:
         done = False
         while not done: