Update tensors.py

never used isort or black before :(
Hope it passes the checks this time.

mathics/builtin/tensors.py

@@ -527,6 +527,14 @@ def eval(self, d, type, evaluation: Evaluation):
         if isinstance(d, Integer) and type == SymbolSparseArray:
             d = d.get_int_value()
             perms = list(permutations([i for i in range(1, d + 1)]))
-            rules = [Expression(SymbolRule, from_python(p), from_python(Permutation.from_sequence(p).signature())) for p in perms]
-            return Expression(SymbolSparseArray, from_python(rules), from_python([d] * d))
-
+            rules = [
+                Expression(
+                    SymbolRule,
+                    from_python(p),
+                    from_python(Permutation.from_sequence(p).signature()),
+                )
+                for p in perms
+            ]
+            return Expression(
+                SymbolSparseArray, from_python(rules), from_python([d] * d)
+            )