docs: def branch(self, branch):
          '''
          .. seealso:: :attr:`branch`
          '''
  
          if not branch:
              branch = self.__mbranch
          tracking = (
              ''
              if branch in self._get_branch(remotes=True).get('out') else
              '-B'
          )
          self._checkout(treeish='%s %s' % (tracking, branch))