(expr)
return _is_form(expr, And, Or)
Test whether or not an expression is in conjunctive normal form.

    Examples
    ========

    >>> from sympy.logic.boolalg import is_cnf
    >>> from sympy.abc import A, B, C
    >>> is_cnf(A | B | C)
    True
    >>> is_cnf(A & B & C)
    True
    >>> is_cnf((A & B) | C)
    False
Test whether or not an expression is in conjunctive normal form.
Test whether or not an expression is in conjunctive normal form .
def is_cnf(expr):
    """
    Test whether or not an expression is in conjunctive normal form.

    Examples
    ========

    >>> from sympy.logic.boolalg import is_cnf
    >>> from sympy.abc import A, B, C
    >>> is_cnf(A | B | C)
    True
    >>> is_cnf(A & B & C)
    True
    >>> is_cnf((A & B) | C)
    False

    """
    return _is_form(expr, And, Or)
def is_cnf ( expr ) : return _is_form ( expr , And , Or )