import itertools


def _merge_dicts(first, second):
    """Merge two dicts into a new one
    Args:
        first (dict): Primary dict; if a key is present in both, the value from this
            dict is used.
        second (dict): Other dict to merge.
    Returns:
        dict: Union of provided dicts, with value from first used in the case of overlap.
    """
    return {k: v for k, v in itertools.chain(second.iteritems(), first.iteritems())}