Minor clean up

lbmpy/methods/momentbased/momentbasedsimplifications.py

@@ -140,6 +140,7 @@ def replace_common_quadratic_and_constant_term(cr: LbmCollisionRule):
         return cr
 
 
+# TODO: This solution is from https://github.com/sympy/sympy/issues/23297. Can be removed if in SymPy master
 def find_subadd(exprs, replacement_symbol_generator):
     exprs = sp.Tuple(*exprs)
     adds = sp.Tuple(*exprs.atoms(sp.Add))
@@ -281,8 +282,8 @@ def substitute_moments_in_conserved_quantity_equations(ac: AssignmentCollection)
 
     for cq_sym, moment_sym in cq_symbols_to_moments.items():
         moment_eq = reduced_assignments[moment_sym]
-        assert moment_eq.count(cq_sym) == 0, "Expressing conserved quantity " \
-                                             f"{cq_sym} using moment {moment_sym} would introduce a circular dependency."
+        assert moment_eq.count(cq_sym) == 0, f"Expressing conserved quantity {cq_sym} using moment {moment_sym} " \
+                                             "would introduce a circular dependency."
         cq_eq = subs_additive(reduced_assignments[cq_sym], moment_sym, moment_eq)
         if cq_sym in main_asm_dict:
             main_asm_dict[cq_sym] = cq_eq