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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 _buildFileUrl(self, xml_req):
 		"""Builds url for fetching the files from FM."""

		return '%(protocol)s://%(host)s:%(port)s%(xml_req)s'%{
			'protocol': self._protocol,
			'host': self._host,
			'port': self._port,
			'xml_req': xml_req,
		}