'Returns a Premier account signed url.'

def get_signed_url(self, params):

    params['client'] = self.client_id
    url_params = {'protocol': self.protocol, 'domain': self.domain, 'params': urlencode(params)}
    secret = base64.urlsafe_b64decode(self.secret_key)
    url_params['url_part'] = ('/maps/api/geocode/json?%(params)s' % url_params)
    signature = hmac.new(secret, url_params['url_part'], hashlib.sha1)
    url_params['signature'] = base64.urlsafe_b64encode(signature.digest())
    return ('%(protocol)s://%(domain)s%(url_part)s&signature=%(signature)s' % url_params)
