code: def _read_config(self):
          
          if not self._file_path:
              return None
          elif self._file_path.startswith('s3://'):
              return self._read_s3_config()
          elif self._file_path.startswith('http://') or \
                  self._file_path.startswith('https://'):
              return self._read_remote_config()
          elif not path.exists(self._file_path):
              raise ValueError(
                  'Configuration file not found: {}'.format(self._file_path))
  
          with open(self._file_path, 'r') as handle:
              return handle.read()
docs: Read the configuration from the various places it may be read from.
  
          :rtype: str
          :raises: ValueError