fix: Update for readability

Author: AyushChakraborty

bit_manipulation/hamming_code_generator.py

@@ -88,8 +88,11 @@ def hamming_15_11(number: str) -> str:
 
         return "".join([str(i) for i in hamming_digits])
 
-    if len(number) != 11 or not is_bin:
+    elif len(number) != 11 or not is_bin:
         return "Input must be an 11-bit binary string containing only '0's and '1's."
+    
+    else:
+        return None
 
 
 if __name__ == "__main__":