code: def getmtime(self, path):
          
          try:
              file_obj = self.filesystem.resolve(path)
              return file_obj.st_mtime
          except IOError:
              self.filesystem.raise_os_error(errno.ENOENT, winerror=3)
docs: Returns the modification time of the fake file.
  
          Args:
              path: the path to fake file.
  
          Returns:
              (int, float) the modification time of the fake file
                           in number of seconds since the epoch.
  
          Raises:
              OSError: if the file does not exist.