<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def htmlentityreplace_errors(ex):
 """An encoding error handler. This python `codecs`_ error handler replaces unencodable characters with HTML entities, or, if no HTML entity exists for the character, XML character references. 'The cost was &euro;12.' """

    if isinstance(ex, UnicodeEncodeError):
        # Handle encoding errors
        bad_text = ex.object[ex.start:ex.end]
        text = _html_entities_escaper.escape(bad_text)
        return (compat.text_type(text), ex.end)
    raise ex