Adopted new convention from template

src/Python/Problems001-050/Problem004.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env python
 """
 Created on 18 Mar 2017
 
@@ -20,9 +20,10 @@ def compute():
 
     Find the largest palindrome made from the product of two 3-digit numbers.
     """
+
     ans = 0
-    for i in range(100, 1000):
-        for j in range(100, 1000):
+    for i in range(100, 1_000):
+        for j in range(100, 1_000):
             palindrome = i * j
             s = str(palindrome)
             if s == s[::-1] and palindrome > ans:
@@ -32,5 +33,4 @@ def compute():
 
 
 if __name__ == "__main__":
-
-    print(f"Result for problem 4: {compute()}")
+    print(f"Result for problem 4 is {compute()}")