diff --git a/conversions/roman_numerals.py b/conversions/roman_numerals.py
index 548620c7a..68f8782d3 100644
--- a/conversions/roman_numerals.py
+++ b/conversions/roman_numerals.py
@@ -1,33 +1,12 @@
 ROMAN = [
-    (1000000, "M_"),
-    (900000, "C_M_"),
-    (500000, "D_"),
-    (400000, "C_D_"),
-    (100000, "C_"),
-    (90000, "X_C_"),
-    (50000, "L_"),
-    (40000, "X_L_"),
-    (10000, "X_"),
-    (9000, "I_X_"),
-    (5000, "V_"),
-    (4000, "I_V_"),
-    (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"),
+(1000000, "M_"), (900000, "C_M_"), (500000, "D_"), (400000, "C_D_"),
+    (100000, "C_"), (90000, "X_C_"), (50000, "L_"), (40000, "X_L_"),
+    (10000, "X_"), (9000, "I_X_"), (5000, "V_"), (4000, "I_V_"),
+    (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: str) -> int:
+def roman_to_int(roman):
     """
     Convert a Roman numeral to an integer, supporting Vinculum notation
     (underscore _ represents 1000 times).
@@ -42,21 +21,20 @@ def roman_to_int(roman: str) -> int:
     >>> all(roman_to_int(key) == value for key, value in tests.items())
     True
     """
-    vals = dict(ROMAN)  # Convert the list of tuples to a dictionary
+    vals = {roman: arabic for arabic, roman in ROMAN}
+    # Convert the list of tuples to a dictionary
 
     i, total = 0, 0
     while i < len(roman):
-        # Check for 2-character symbols first (like I_ or X_)
-        if i + 1 < len(roman) and roman[i : i + 2] in vals:
-            total += vals[roman[i : i + 2]]
+        # 先匹配 2 个字符的罗马数字（如 I_、X_）
+        if i + 1 < len(roman) and roman[i:i+2] in vals:
+            total += vals[roman[i:i+2]]
             i += 2
         else:
             total += vals[roman[i]]
             i += 1
     return total
-
-
-def int_to_roman(number: int) -> str:
+def int_to_roman(number):
     """
     Convert an integer to a Roman numeral, supporting Vinculum notation
     (underscore _ represents 1000 times).
@@ -78,9 +56,7 @@ def int_to_roman(number: int) -> str:
         if number == 0:
             break
     return "".join(result)
-
-
+    
 if __name__ == "__main__":
     import doctest
-
     doctest.testmod()