def forward(self, x, emb, y=None):
    for layer in self:
        if isinstance(layer, TimestepBlock):
            x = layer(x, emb)
        elif isinstance(layer, ConditionalBlock):
            x = layer(x, y=y)
        else:
            x = layer(x)
    return x
def forward(self, x, emb, y=None):
    for layer in self:
        if isinstance(layer, TimestepBlock):
            x = layer(x, emb)
        elif isinstance(layer, ConditionalBlock):
            x = layer(x, y=y)
        else:
            x = layer(x)
    return x