diff --git a/src/caoscrawler/xml_converter.py b/src/caoscrawler/xml_converter.py
index 4c7242559c323224d7e62d068ae8a7d75a604b9a..6d350c26d467372e65c4acc0fd397d6679279b24 100644
--- a/src/caoscrawler/xml_converter.py
+++ b/src/caoscrawler/xml_converter.py
@@ -93,7 +93,7 @@ class XMLTagConverter(Converter):
             tags_as_children: true  # _true_ / false
 
         The default is to generate the tags matched by the xpath expression only.
-        
+
         - When text_as_children is set to true, text nodes will be generated that contain the text
           contained in the matched tags.
         - When attribs_as_children is set to true, attribute nodes will be generated from the attributes
@@ -129,7 +129,8 @@ class XMLTagConverter(Converter):
         el_lst = []
         for el in children:
             if isinstance(el, str):
-                raise RuntimeError("Only standard xml nodes are supported as results of xpath queries.")
+                raise RuntimeError(
+                    "Only standard xml nodes are supported as results of xpath queries.")
             elif isinstance(el, lxml.etree._Element):
                 if self.definition.get("tags_as_children", True):
                     el_lst.append(XMLTagElement(el))