code: def get_module(self, modulename, revision=None):
          
          if revision is None and modulename in self.revs:
              (revision, _handle) = self._get_latest_rev(self.revs[modulename])
          if revision is not None:
              if (modulename,revision) in self.modules:
                  return self.modules[(modulename, revision)]
          else:
              return None
docs: Return the module if it exists in the context