(formula)
return get_env().fvo.get_free_variables(formula)
Returns the free variables of the formula.

    :param formula: The target formula
    :type  formula: FNode
    :returns: Free variables in the formula
Returns the free variables of the formula.
Returns the free variables of the formula .
def get_free_variables(formula):
    """Returns the free variables of the formula.

    :param formula: The target formula
    :type  formula: FNode
    :returns: Free variables in the formula
    """
    return get_env().fvo.get_free_variables(formula)
def get_free_variables ( formula ) : return get_env ( ) . fvo . get_free_variables ( formula )