added assignment to simplified_term for simplify_product_function

src/main/py/read_math_function.py

@@ -101,4 +101,5 @@ def simplify_product_function(type, function):
     for term in terms:
         simplified_term = simplify_easy_math_function("v", term.strip())
         if not simplified_term or len(simplified_term) != 2:
-            return False
+            return False
+        term_coefficient, term_variables = simplified_term