human
Solve the following python programming problem given the following code:
@ classmethod 
def forTypes(klass, key, classes, description, extraValidator = None) : 
    '
        Create a L{Field} that must be an instance of a given set of types.

        @param key: The name of the field, the key which refers to it,
            e.g. C{"path"}.

        @ivar classes: A C{list} of allowed Python classes for this field\'s
            values. Supported classes are C{unicode}, C{int}, C{float},
            C{bool}, C{long}, C{list} and C{dict} and C{None} (the latter
            isn\'t strictly a class, but will be converted appropriately).

        @param description: A description of what this field contains.
        @type description: C{unicode}

        @param extraValidator: See description in L{Field.__init__}.

        @return: A L{Field}.
        ' 
    fixedClasses = [] 
    for k in classes : 
        if (k is None) : 
            k = type (None) 
if (k not in _JSON_TYPES) : 
            raise TypeError (('%s is not JSON-encodeable' % (k,))) 
fixedClasses.append (k) 
fixedClasses = tuple (fixedClasses) 
    def validate(value) : 
        if (not isinstance (value, fixedClasses)) : 
            raise ValidationError (value, ('Field %r requires type to be one of %s' % (key, classes))) 
if (extraValidator is not None) : 
            extraValidator (value) 
return klass (key, (lambda v : v), klass, extraValidator = validate) 

    
    

    Fix the buggy line: return klass (key, (lambda v : v), klass, extraValidator = validate)
assistant
#Here is Python program to fix the buggy line: return klass (key, (lambda v : v), klass, extraValidator = validate)
.

return klass (key, (lambda v : v), description, extraValidator = validate)