gh-40313: code simplification about return True then False (ruff SIM 103)
    
simpler code in various files, all about how to return boolean in a
better way

### 📝 Checklist

- [x] The title is concise and informative.
- [x] The description explains in detail what this PR is about.
- [ ] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation and checked the documentation
preview.
    
URL: #40313
Reported by: Frédéric Chapoton
Reviewer(s): Frédéric Chapoton, Martin Rubey

Author: Release Manager

src/sage/algebras/free_zinbiel_algebra.py

@@ -671,7 +671,8 @@ def __init__(self, variables, side):
         Functor.__init__(self, Rings(), Magmas())
         self.vars = variables
         self._side = side
-        self._finite_vars = bool(isinstance(variables, (list, tuple)) or variables in Sets().Finite())
+        self._finite_vars = (isinstance(variables, (list, tuple))
+                             or variables in Sets().Finite())
 
     def _apply_functor(self, R):
         """

src/sage/algebras/fusion_rings/f_matrix.py

@@ -1817,7 +1817,7 @@ def _get_component_variety(self, var, eqns):
     # TODO: this can probably be improved by constructing a set of defining polynomials
     # and checking, one by one, if it's irreducible over the current field.
     # If it is, we construct an extension. Perhaps it's best to go one by one here...
-    def attempt_number_field_computation(self):
+    def attempt_number_field_computation(self) -> bool:
         r"""
         Based on the ``CartanType`` of ``self`` and data
         known on March 17, 2021, determine whether to attempt

src/sage/algebras/shuffle_algebra.py

@@ -539,10 +539,7 @@ def _coerce_map_from_(self, R):
         # shuffle algebras in the same variable over any base that coerces in:
         if isinstance(R, ShuffleAlgebra):
             if R.variable_names() == self.variable_names():
-                if self.base_ring().has_coerce_map_from(R.base_ring()):
-                    return True
-                else:
-                    return False
+                return self.base_ring().has_coerce_map_from(R.base_ring())
 
         if isinstance(R, DualPBWBasis):
             return self.has_coerce_map_from(R._alg)

src/sage/combinat/cartesian_product.py

@@ -292,9 +292,7 @@ def is_finite(self):
         if all(f is True for f in finites):
             return True
         lens = [_len(L) for L in self.iters]
-        if any(l == 0 for l in lens):
-            return True
-        return False
+        return any(l == 0 for l in lens)
 
     def unrank(self, x):
         """

src/sage/combinat/designs/difference_family.py

@@ -1307,9 +1307,7 @@ def _is_periodic_sequence(seq, period):
                 break
         if periodic:
             return False
-    if seq[:period] != seq[period : 2*period]:
-        return False
-    return True
+    return seq[:period] == seq[period:2 * period]
 
 
 def _create_m_sequence(q, n, check=True):

src/sage/combinat/gelfand_tsetlin_patterns.py

@@ -704,10 +704,9 @@ def __contains__(self, gt):
                    for i in range(1, len(gt)) for j in range(len(gt[i]))):
             return False
         # Check if it is strict if applicable
-        if self._strict and any(gt[i][j] == gt[i][j-1] for i in range(len(gt))
-                                for j in range(1, len(gt[i]))):
-            return False
-        return True
+        return not (self._strict and any(gt[i][j] == gt[i][j - 1]
+                                         for i in range(len(gt))
+                                         for j in range(1, len(gt[i]))))
 
     def _repr_(self):
         """

src/sage/combinat/integer_matrices.py

@@ -178,9 +178,7 @@ def __contains__(self, x):
                 col_sums[j] += x_ij
             if row_sums[i] != self._row_sums[i]:
                 return False
-        if col_sums != self._col_sums:
-            return False
-        return True
+        return col_sums == self._col_sums
 
     def cardinality(self):
         r"""

src/sage/combinat/integer_vector.py

@@ -1310,10 +1310,7 @@ def __contains__(self, x):
         if sum(x) != self.n:
             return False
 
-        if len(x) > 0 and min(x) < 0:
-            return False
-
-        return True
+        return not x or min(x) >= 0
 
     def rank(self, x):
         """

src/sage/combinat/matrices/latin.py

@@ -728,10 +728,7 @@ def is_latin_square(self):
             return False
 
         # By necessity self must be a partial latin square:
-        if not self.is_partial_latin_square():
-            return False
-
-        return True
+        return self.is_partial_latin_square()
 
     def permissable_values(self, r, c):
         """

src/sage/combinat/parallelogram_polyomino.py

@@ -3143,9 +3143,7 @@ def box_is_node(self, pos) -> bool:
             return False
         if self[pos[0] - 1][pos[1]] == 0:
             return True
-        if self[pos[0]][pos[1] - 1] == 0:
-            return True
-        return False
+        return self[pos[0]][pos[1] - 1] == 0
 
     def box_is_root(self, box) -> bool:
         r"""