Update butterfly_pattern.py

Author: MaximSmolskiy

graphics/butterfly_pattern.py

@@ -8,16 +8,29 @@ def butterfly_pattern(n: int) -> str:
     *****
     ** **
     *   *
+    >>> print(butterfly_pattern(5))
+    *       *
+    **     **
+    ***   ***
+    **** ****
+    *********
+    **** ****
+    ***   ***
+    **     **
+    *       *
     """
     result = []
 
     # Upper part
-    for i in range(1, n + 1):
+    for i in range(1, n):
         left_stars = "*" * i
         spaces = " " * (2 * (n - i) - 1)
         right_stars = "*" * i
         result.append(left_stars + spaces + right_stars)
 
+    # Middle part
+    result.append("*" * (2 * n - 1))
+
     # Lower part
     for i in range(n - 1, 0, -1):
         left_stars = "*" * i