'Initialize the CredentialInstance
:returns: twilio.rest.api.v2010.account.sip.credential_list.credential.CredentialInstance
:rtype: twilio.rest.api.v2010.account.sip.credential_list.credential.CredentialInstance'

def __init__(self, version, payload, account_sid, credential_list_sid, sid=None):

    super(CredentialInstance, self).__init__(version)
    self._properties = {'sid': payload['sid'], 'account_sid': payload['account_sid'], 'credential_list_sid': payload['credential_list_sid'], 'username': payload['username'], 'date_created': deserialize.rfc2822_datetime(payload['date_created']), 'date_updated': deserialize.rfc2822_datetime(payload['date_updated']), 'uri': payload['uri']}
    self._context = None
    self._solution = {'account_sid': account_sid, 'credential_list_sid': credential_list_sid, 'sid': (sid or self._properties['sid'])}
