def islazy(x):
    """Check if x is a lazy evaluation

    >>> islazy((x for x in range(10)))
    True

    >>> islazy('')
    False

    >>> islazy(dict(a=1))
    False
    """
    return (
        hasattr(x, '__iter__')
        and not isinstance(x, str)    
        and not isinstance(x, dict)   
        and not isinstance(x, set)
        )