diff --git a/src/sage/combinat/cluster_algebra_quiver/mutation_type.py b/src/sage/combinat/cluster_algebra_quiver/mutation_type.py
index 5578e751b5d..ef8aaab5e54 100644
--- a/src/sage/combinat/cluster_algebra_quiver/mutation_type.py
+++ b/src/sage/combinat/cluster_algebra_quiver/mutation_type.py
@@ -149,7 +149,7 @@ def _triangles(dg):
     return trians
 
 
-def _all_induced_cycles_iter( dg ):
+def _all_induced_cycles_iter(dg):
     """
     Return an iterator for all induced oriented cycles of length
     greater than or equal to 4 in the digraph ``dg``.
@@ -356,9 +356,9 @@ def _connected_mutation_type(dg):
     for edge in edges:
         label = edge[2]
         if label not in [(1,-1),(2,-2),(1,-2),(2,-1),(4,-1),(1,-4)]:
-    # _false_return(i) is a simple function that simply returns 'unknown'.  For debugging purposes, it
-    # can also output 'DEBUG: error i' if desired.
-    # this command is used many times in this code, something times without the argument i.
+            # _false_return(i) is a simple function that simply returns 'unknown'.  For debugging purposes, it
+            # can also output 'DEBUG: error i' if desired.
+            # this command is used many times in this code, something times without the argument i.
             return _false_return(2)
         elif label == (2,-2):
             dg.set_edge_label( edge[0], edge[1], 1 )
@@ -1032,7 +1032,7 @@ def _connected_mutation_type_AAtildeD(dg, ret_conn_vert=False):
             test_triangles = [[tuple(trian) for trian in oriented_trians
                                if edge in trian]
                               for edge in multiple_trian_edges]
-            unique_triangle = set(test_triangles[0]).intersection( *test_triangles[1:] )
+            unique_triangle = set.intersection(*map(set, test_triangles))
             if len(unique_triangle) != 1:
                 return _false_return(19)
             else:
@@ -1299,7 +1299,7 @@ def load_data(n, user=True):
     return data
 
 
-def _mutation_type_from_data( n, dig6, compute_if_necessary=True ):
+def _mutation_type_from_data(n, dig6, compute_if_necessary=True):
     r"""
     Return the mutation type from the given dig6 data by looking into
     the precomputed mutation types
@@ -1506,7 +1506,7 @@ def _random_tests(mt, k, mut_class=None, nr_mut=5):
                     dg = dg_new
 
 
-def _random_multi_tests( n, k, nr_mut=5 ):
+def _random_multi_tests(n, k, nr_mut=5):
     """
     Provide multiple random tests to find bugs in the mutation type methods.
 
diff --git a/src/sage/combinat/plane_partition.py b/src/sage/combinat/plane_partition.py
index bc523121623..8f4ded21d16 100644
--- a/src/sage/combinat/plane_partition.py
+++ b/src/sage/combinat/plane_partition.py
@@ -314,17 +314,19 @@ def x_tableau(self, tableau=True) -> Tableau:
             return Tableau(X)
         return X
 
-    def cells(self) -> list[list[int]]:
+    def cells(self) -> list[tuple[int, int, int]]:
         r"""
         Return the list of cells inside ``self``.
 
+        Each cell is a tuple.
+
         EXAMPLES::
 
             sage: PP = PlanePartition([[3,1],[2]])
             sage: PP.cells()
-            [[0, 0, 0], [0, 0, 1], [0, 0, 2], [0, 1, 0], [1, 0, 0], [1, 0, 1]]
+            [(0, 0, 0), (0, 0, 1), (0, 0, 2), (0, 1, 0), (1, 0, 0), (1, 0, 1)]
         """
-        return [[r, c, h]
+        return [(r, c, h)
                 for r in range(len(self))
                 for c in range(len(self[r]))
                 for h in range(self[r][c])]
diff --git a/src/sage/combinat/tableau.py b/src/sage/combinat/tableau.py
index 7613ef9a671..d5ebaee709c 100644
--- a/src/sage/combinat/tableau.py
+++ b/src/sage/combinat/tableau.py
@@ -2618,7 +2618,7 @@ def slide_multiply(self, other):
 
         l = len(self[0])
         st = [(None,) * l + row for row in other]
-        st.extend(row for row in self)
+        st.extend(self)
 
         from sage.combinat.skew_tableau import SkewTableau
         return SkewTableau(st).rectify()