code: def read(self, size=None):
      
  
      if size is None:
        self.temporary_file.seek(0)
        data = self.temporary_file.read()
        self.temporary_file.seek(0)
  
        return data
  
      else:
        if not (isinstance(size, int) and size > 0):
          raise securesystemslib.exceptions.FormatError
  
        return self.temporary_file.read(size)
docs: <Purpose>
        Read specified number of bytes.  If size is not specified then the whole
        file is read and the file pointer is placed at the beginning of the file.
  
      <Arguments>
        size:
          Number of bytes to be read.
  
      <Exceptions>
        securesystemslib.exceptions.FormatError: if 'size' is invalid.
  
      <Return>
        String of data.