diff --git a/trafilatura/utils.py b/trafilatura/utils.py
index 84fcfd3c..4ff5e941 100644
--- a/trafilatura/utils.py
+++ b/trafilatura/utils.py
@@ -462,7 +462,7 @@ def copy_attributes(dest_elem: _Element, src_elem: _Element) -> None:
         dest_elem.set(key, src_elem.attrib[key])
 
 
-def is_in_table_cell(elem: _Element) -> bool:
+def is_in_table_cell(elem: Optional[_Element]) -> bool:
     '''Check whether an element is in a table cell'''
     while elem is not None:
         if elem.tag == 'cell':