# A more or less complete user-defined wrapper around list objects

class UserList:
	def __init__(self, list = None):
		self.data = []
		if list is not None:
			if type(list) == type(self.data):
				self.data[:] = list
			else:
				self.data[:] = list.data[:]
	def __repr__(self): return repr(self.data)
	def __cmp__(self, list):
		if type(list) == type(self.data):
			return cmp(self.data, list)
		else:
			return cmp(self.data, list.data)
	def __len__(self): return len(self.data)
	def __getitem__(self, i): return self.data[i]
	def __setitem__(self, i, item): self.data[i] = item
	def __delitem__(self, i): del self.data[i]
	def __getslice__(self, i, j):
		userlist = self.__class__()
		userlist.data[:] = self.data[i:j]
		return userlist
	def __setslice__(self, i, j, list):
		if type(list) == type(self.data):
			self.data[i:j] = list
		else:
			self.data[i:j] = list.data
	def __delslice__(self, i, j): del self.data[i:j]
	def __add__(self, list):
		if type(list) == type(self.data):
			return self.__class__(self.data + list)
		else:
			return self.__class__(self.data + list.data)
	def __radd__(self, list):
		if type(list) == type(self.data):
			return self.__class__(list + self.data)
		else:
			return self.__class__(list.data + self.data)
	def __mul__(self, n):
		return self.__class__(self.data*n)
	__rmul__ = __mul__
	def append(self, item): self.data.append(item)
	def insert(self, i, item): self.data.insert(i, item)
	def pop(self, i=-1): return self.data.pop(i)
	def remove(self, item): self.data.remove(item)
	def count(self, item): return self.data.count(item)
	def index(self, item): return self.data.index(item)
	def reverse(self): self.data.reverse()
	def sort(self, *args): apply(self.data.sort, args)
	def extend(self, list): self.data.extend(list)

# A more or less complete user-defined wrapper around list objects

class UserList:
    def __init__(self, list=None):
        self.data = []
        if list is not None:
            if type(list) == type(self.data):
                self.data[:] = list
            else:
                self.data[:] = list.data[:]
    def __repr__(self): return repr(self.data)
    def __cmp__(self, other):
        if isinstance(other, UserList):
            return cmp(self.data, other.data)
        else:
            return cmp(self.data, other)
    def __len__(self): return len(self.data)
    def __getitem__(self, i): return self.data[i]
    def __setitem__(self, i, item): self.data[i] = item
    def __delitem__(self, i): del self.data[i]
    def __getslice__(self, i, j):
        i = max(i, 0); j = max(j, 0)
        userlist = self.__class__()
        userlist.data[:] = self.data[i:j]
        return userlist
    def __setslice__(self, i, j, other):
        i = max(i, 0); j = max(j, 0)
        if isinstance(other, UserList):
            self.data[i:j] = other.data
        elif isinstance(other, type(self.data)):
            self.data[i:j] = other
        else:
            self.data[i:j] = list(other)
    def __delslice__(self, i, j):
        i = max(i, 0); j = max(j, 0)
        del self.data[i:j]
    def __add__(self, other):
        if isinstance(other, UserList):
            return self.__class__(self.data + other.data)
        elif isinstance(other, type(self.data)):
            return self.__class__(self.data + other)
        else:
            return self.__class__(self.data + list(other))
    def __radd__(self, other):
        if isinstance(other, UserList):
            return self.__class__(other.data + self.data)
        elif isinstance(other, type(self.data)):
            return self.__class__(other + self.data)
        else:
            return self.__class__(list(other) + self.data)
    def __mul__(self, n):
        return self.__class__(self.data*n)
    __rmul__ = __mul__
    def append(self, item): self.data.append(item)
    def insert(self, i, item): self.data.insert(i, item)
    def pop(self, i=-1): return self.data.pop(i)
    def remove(self, item): self.data.remove(item)
    def count(self, item): return self.data.count(item)
    def index(self, item): return self.data.index(item)
    def reverse(self): self.data.reverse()
    def sort(self, *args): apply(self.data.sort, args)
    def extend(self, other):
        if isinstance(other, UserList):
            self.data.extend(other.data)
        else:
            self.data.extend(other)

Use isinstance() where appropriate. Reformatted with 4-space indent.