docs: def merge_env(self, env):
          """
          :param env:
          :return:
          """
          # convert to dict to allow update
          current_env = dict(item.split('=') for item in self._env)
  
          # do validation and set new values.
          self.env = env
  
          # convert to dict to allow update
          new_env = dict(item.split('=') for item in self._env)
  
          # update old with new
          current_env.update(new_env)
  
          # apply updated values
          self.env = current_env