Fix source_code function with the dynamic answer class.

chatmastermind/message.py

@@ -51,7 +51,7 @@ def source_code(text: str, include_delims: bool = False) -> list[str]:
     code_lines: list[str] = []
     in_code_block = False
 
-    for line in text.split('\n'):
+    for line in str(text).split('\n'):
         if line.strip().startswith('```'):
             if include_delims:
                 code_lines.append(line)