'Include or update the specified `data` payload in the PayloadManager.
If a previous payload with the same source exists and `single` is True,
it will be overwritten with the new one.'

def write_payload(self, data, single=True):

    if (not isinstance(data, dict)):
        raise TypeError(('Each    payload    write    must    be    a    dict,    got:    %r' % data))
    if (single and ('source' in data)):
        source = data['source']
        for (i, pl) in enumerate(self._payload):
            if (('source' in pl) and (pl['source'] == source)):
                self._payload[i] = data
                return
    self._payload.append(data)
