Deprecated built-in function __getslice__ in python 3.7 to get a slice from a list

[gorhan]

To get the interval of a list object is handled inside the getitem built-in function. Since it only checks whether given parameter to this function is int or not, the slice objects enters the else statement which causes a problem. Possible Fix:

def __getitem__(self, expr):
    if type(expr) is int or type(expr) is slice:
        return list.__getitem__(self, expr)
    else:
        return Element(self, expr)

Thank you.