Converts HTML5 character references within text_string to their corresponding unicode characters
    and returns converted string as type str.

    Keyword argument:

    - text_string: string instance

    Exceptions raised:

    - InputError: occurs should a non-string argument be passed

def convert_html_entities(text_string):
    '''
    Converts HTML5 character references within text_string to their corresponding unicode characters
    and returns converted string as type str.

    Keyword argument:

    - text_string: string instance

    Exceptions raised:

    - InputError: occurs should a non-string argument be passed
    '''
    if text_string is None or text_string == "":
        return ""
    elif isinstance(text_string, str):
        return html.unescape(text_string).replace("&quot;", "'")
    else:
        raise InputError("string not passed as argument for text_string")