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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def ext_pillar(minion_id,
               pillar,  # pylint: disable=W0613
               url,
               with_grains=False):
    '''
    Read pillar data from HTTP response.

    :param str url: Url to request.
    :param bool with_grains: Whether to substitute strings in the url with their grain values.

    :return: A dictionary of the pillar data to add.
    :rtype: dict
    '''

    url = url.replace('%s', _quote(minion_id))

    grain_pattern = r'<(?P<grain_name>.*?)>'

    if with_grains:
        # Get the value of the grain and substitute each grain
        # name for the url-encoded version of its grain value.
        for match in re.finditer(grain_pattern, url):
            grain_name = match.group('grain_name')
            grain_value = __salt__['grains.get'](grain_name, None)

            if not grain_value:
                log.error("Unable to get minion '%s' grain: %s", minion_id, grain_name)
                return {}

            grain_value = _quote(six.text_type(grain_value))
            url = re.sub('<{0}>'.format(grain_name), grain_value, url)

    log.debug('Getting url: %s', url)
    data = __salt__['http.query'](url=url, decode=True, decode_type='json')

    if 'dict' in data:
        return data['dict']

    log.error("Error on minion '%s' http query: %s\nMore Info:\n", minion_id, url)

    for key in data:
        log.error('%s: %s', key, data[key])

    return {}