from typing import Optional


def convert_docblock(doc: Optional[str]) -> Optional[str]:
    """Strip the comment syntax out of a docblock."""
    if not isinstance(doc, str):
        return doc
    doc = doc.strip('/*')
    lines = doc.split('\n')
    lines = [line.strip() for line in lines]
    lines = [line[1:] if line.startswith('*') else line
             for line in lines]
    return '\n'.join(lines)