import tensorflow as tf


    Subclasses can override this function in order to preprocess, and can
    yield any number of strings.

    Args:
      filepath: a string
    Yields:
      unicode strings.
    """
    f = tf.gfile.Open(filepath)
    b = f.read()
    yield text_encoder.to_unicode_ignore_errors(b)

  def file_generator(self,
                     filepaths,
                     max_chars_per_file=None,
                     max_chars_total=None):
    """Read complete text of input files and yield unicode strings.
