diff --git a/calculate/templates/format/regex_format.py b/calculate/templates/format/regex_format.py
index 8d36d9c..cebbf0e 100644
--- a/calculate/templates/format/regex_format.py
+++ b/calculate/templates/format/regex_format.py
@@ -111,6 +111,7 @@ class RegexFormat(Format):
                         break
 
                 if patch_element.tag == patch_tag:
+                    # Если <reg> тег пустой -- это ошибка.
                     if patch_element.text is not None:
                         element_text = patch_element.text
                         if patch_tag == "reg" and element_text.strip() == '':