Fix and() for SDXL damian0815#78

Closes damian0815#78

src/compel/compel.py

@@ -188,7 +188,9 @@ def build_conditioning_tensor_for_conjunction(self, conjunction: Conjunction) ->
             weight = conjunction.weights[i]
             if weight != 1:
                 # apply weight if we need to
-                empty_conditioning = self.build_conditioning_tensor('') if empty_conditioning is None else empty_conditioning
+                if empty_conditioning is None:
+                    empty_conditioning = self.build_conditioning_tensor('')
+                    if isinstance(empty_conditioning, tuple): empty_conditioning = empty_conditioning[0] # discard pooled
                 [padded_empty_conditioning, _] = self.pad_conditioning_tensors_to_same_length([empty_conditioning, this_conditioning])
                 this_conditioning = padded_empty_conditioning + (this_conditioning - padded_empty_conditioning) * weight
             to_concat.append(this_conditioning)