Hello, While following the iterparse / modifying the tree docs (https://lxml.de/4.5/parsing.html#modifying-the-tree) in attempt to clean up preceding siblings, code raises a TypeError: 'NoneType' object does not support item deletion when the XML contains a comment preceding the root element. Please advise on a workaround for this use case if this is not a potential bug. See below reproducible example. Thank you for your time and review. ```python from io import BytesIO import lxml.etree as ET xml_txt = '''\ <!-- it will choke on this comment --> <issue> <type>BUG</type> </issue> '''.encode('utf-8') iterparse_columns = { "issue": ["type"] } data = [] for event, elem in ET.iterparse(BytesIO(xml_txt), events=('start', 'end')): node = next(iter(iterparse_columns)) curr_elem = ( elem.tag.split('}')[1] if '}' in elem.tag else elem.tag ) if event == 'start': if curr_elem == node: row = {} for col in iterparse_columns[node]: if curr_elem == col: row[col] = ( elem.text.strip() if elem.text is not None else elem.text ) if col in elem.attrib: row[col] = elem.attrib[col].strip() if event == 'end': if curr_elem == node: data.append(row) elem.clear() while elem.getprevious() is not None: del elem.getparent()[0] print(data) ``` Full traceback: ``` Traceback (most recent call last): File "iterparse_parent_comment_reprex.py", line 43, in <module> del elem.getparent()[0] TypeError: 'NoneType' object does not support item deletion ```