Copying and merging environment variables.

        Args:
            include_os (bool): when true then include the environment variables (default: False)

        Returns:
            dict: environment variables as defined in the pipeline
                  (optional including system environment variables).

def get_merged_env(self, include_os=False):
        """
        Copying and merging environment variables.

        Args:
            include_os (bool): when true then include the environment variables (default: False)

        Returns:
            dict: environment variables as defined in the pipeline
                  (optional including system environment variables).
        """
        env = {}
        if include_os:
            env.update(os.environ.copy())
        for level in range(3):
            env.update(self.pipeline.data.env_list[level].copy())
        return env