refactoring: changed == False and == True to is False and is True

src/main/py/read_math_function.py

@@ -50,7 +50,7 @@ def calculate_constant_string(string):
 def simplify_easy_math_function(type, function):
     if type != "v":
         return False
-    if is_string(function) == False or is_allowed_string("c", function) == True:
+    if is_string(function) is False or is_allowed_string("c", function) is True:
         return simplify_constant("c", function)