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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 _HasFile(self, file_name):
 """Returns True if there's a file in the current feed with the given file_name in the current feed."""

    if self._zip:
      return file_name in self._zip.namelist()
    else:
      file_path = os.path.join(self._path, file_name)
      return os.path.exists(file_path) and os.path.isfile(file_path)