'Create a new CredentialInstance
:param unicode username: The username
:param unicode password: The password
:returns: Newly created CredentialInstance
:rtype: twilio.rest.api.v2010.account.sip.credential_list.credential.CredentialInstance'

def create(self, username, password):

    data = values.of({'Username': username, 'Password': password})
    payload = self._version.create('POST', self._uri, data=data)
    return CredentialInstance(self._version, payload, account_sid=self._solution['account_sid'], credential_list_sid=self._solution['credential_list_sid'])
