code: def _writeMzmlChecksum(xmlWriter, outputFile):
      
      sha = hashlib.sha1(outputFile.getvalue())
      sha.update('<fileChecksum>')
  
      xmlChecksumElement = ETREE.Element('fileChecksum')
      xmlChecksumElement.text = sha.hexdigest()
  
      xmlWriter.write(xmlChecksumElement, pretty_print=True)
docs: #TODO: docstring
  
      :param xmlWriter: #TODO: docstring
      :param outputFile: #TODO: docstring