. Python code
[*source, python]
----
def header_anchor(text, level):
    """
    Return a sanitised anchor for a header.
    """

    # Everything lowercase
    sanitised_text = text.lower()

    # Get only letters, numbers, dashes, spaces, and dots
    sanitised_text = "".join(re.findall("[a-z0-9-\\. ]+", sanitised_text))

    # Remove multiple spaces
    sanitised_text = "-".join(sanitised_text.split())

    return sanitised_text
----
