human
Solve the following python programming problem given the following code:
@ classmethod 
def mixin(cls, mixin_cls) : 
    'Decorator for mixing in additional functionality into field type

        Example:

        >>> @Integer.mixin
        ... class IntegerPostgresExtensions:
        ...     postgres_type = \'INT\'
        ...
        ...     def postgres_dump(self, obj):
        ...         self.dump(obj) + "::integer"

        Is roughly equivalent to:

        >>> Integer.postgres_type = \'INT\'
        ...
        ... def postgres_dump(self, obj):
        ...     self.dump(obj) + "::integer"
        ...
        ... Integer.postgres_dump = postgres_dump

        ' 
    for item_name in dir (mixin_cls) : 
        if item_name.startswith ('__') : 
            continue 
item = getattr (mixin_cls, item_name) 
        if isinstance (mixin_cls, types.MethodType) : 
            item = item.im_func 
setattr (cls, item_name, item) 
return mixin_cls 

    
    

    Fix the buggy line: if isinstance (mixin_cls, types.MethodType) :
assistant
#Here is Python code to fix the buggy line: if isinstance (mixin_cls, types.

if isinstance (item, types.MethodType) :