refactoring: simplified by removing unnecessary variable

src/main/py/read_math_function.py

@@ -10,5 +10,4 @@ def is_string(value):
 
 def is_allowed_string(type, value):
     allowed = "+-*/()^"
-    result = all(character.isdigit() or character in allowed for character in value)
-    return result
+    return all(character.isdigit() or character in allowed for character in value)