def simplest_form(expr, **kwargs):
    """Finds the shortest simplification for the given expression."""
    cnf_expr = expr.simplify(dnf=False, **kwargs)
    dnf_expr = cnf_expr.simplify(dnf=True, **kwargs)
    if len(cnf_expr) <= len(dnf_expr):
        return cnf_expr
    else:
        return dnf_expr