def METHOD_NAME(self):
    self._log.debug("Cloning [%s] to [%s]", self._url, self.bp_dir)
    stream_output(self._stream,
                  " ".join(['git', 'clone', self._url, self.bp_dir]),
                  stderr=subprocess.STDOUT,
                  shell=True)
    if self._branch:
        self._log.debug("Branching to [%s]", self._branch)
        stream_output(self._stream,
                      " ".join(['git', 'checkout', self._branch]),
                      stderr=subprocess.STDOUT,
                      shell=True)