:param env:
        :return:

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