code: def _starts_with_drive_letter(self, file_path):
          
          colon = self._matching_string(file_path, ':')
          return (self.is_windows_fs and len(file_path) >= 2 and
                  file_path[:1].isalpha and (file_path[1:2]) == colon)
docs: Return True if file_path starts with a drive letter.
  
          Args:
              file_path: the full path to be examined.
  
          Returns:
              `True` if drive letter support is enabled in the filesystem and
              the path starts with a drive letter.