def cmp_subst(subst_1, subst_2):
    """Compare two substitution sets.

    :arg dict subst_1: Substitution set.
    :arg dict subst_2: Substitution set.

    :returns bool: True if `subst_1` equals `subst2`, False otherwise.
    """
    if len(subst_1) != len(subst_2):
        return False

    for item in subst_1:
        if subst_1[item] != subst_2[item]:
            return False

    return True