Fix range error with docstrings

utils/tree_utils.py

@@ -99,6 +99,8 @@ def grab_before_comments(func_node):
             precomment += node.text.decode() + "\n"
             last_comment_line = node.start_point[0]
         elif node == func_node:
+            if precomment == "":
+                start_byte = node.start_byte
             return precomment, start_byte
     return precomment, start_byte