<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _decoder(self, obj):
 """ Decode a toc element leaf-node """

        if '__class__' in obj:
            elem = eval(obj['__class__'])()
            elem.ident = obj['ident']
            elem.group = str(obj['group'])
            elem.name = str(obj['name'])
            elem.ctype = str(obj['ctype'])
            elem.pytype = str(obj['pytype'])
            elem.access = obj['access']
            return elem
        return obj