diff --git a/conversions/roman_numerals.py b/conversions/roman_numerals.py
index 7a22dd68b..12a9e49b2 100644
--- a/conversions/roman_numerals.py
+++ b/conversions/roman_numerals.py
@@ -1,20 +1,33 @@
 ROMAN_NUMERALS = {
-    1000: "M", 900: "CM", 500: "D", 400: "CD", 100: "C",
-    90: "XC", 50: "L", 40: "XL", 10: "X", 9: "IX", 5: "V", 4: "IV", 1: "I"
+    1000: "M",
+    900: "CM",
+    500: "D",
+    400: "CD",
+    100: "C",
+    90: "XC",
+    50: "L",
+    40: "XL",
+    10: "X",
+    9: "IX",
+    5: "V",
+    4: "IV",
+    1: "I",
 }
 
+
 def roman_to_int(roman):
     result = 0
     i = 0
     while i < len(roman):
-        if i + 1 < len(roman) and roman[i:i+2] in ROMAN_NUMERALS:
-            result += ROMAN_NUMERALS[roman[i:i+2]]
+        if i + 1 < len(roman) and roman[i : i + 2] in ROMAN_NUMERALS:
+            result += ROMAN_NUMERALS[roman[i : i + 2]]
             i += 2
         else:
             result += ROMAN_NUMERALS[roman[i]]
             i += 1
     return result
 
+
 def int_to_roman(number):
     result = ""
     for value, numeral in ROMAN_NUMERALS.items():
@@ -23,6 +36,8 @@ def int_to_roman(number):
             number -= value
     return result
 
+
 if __name__ == "__main__":
     import doctest
+
     doctest.testmod()