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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_help_for_modules(self, modules, prefix, include_special_flags):
 """Returns the help string for a list of modules. Private to absl.flags package. Args: modules: List[str], a list of modules to get the help string for. prefix: str, a string that is prepended to each generated help line. include_special_flags: bool, whether to include description of SPECIAL_FLAGS, i.e. --flagfile and --undefok. """

    output_lines = []
    for module in modules:
      self._render_our_module_flags(module, output_lines, prefix)
    if include_special_flags:
      self._render_module_flags(
          'absl.flags',
          six.itervalues(_helpers.SPECIAL_FLAGS._flags()),  # pylint: disable=protected-access
          output_lines,
          prefix)
    return '\n'.join(output_lines)