def create(self, username, password):
        """
        Create a new CredentialInstance

        :param unicode username: The username for this credential.
        :param unicode password: The password will not be returned in the response.

        :returns: Newly created CredentialInstance
        :rtype: twilio.rest.api.v2010.account.sip.credential_list.credential.CredentialInstance
        """
        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'],
        )
Create a new CredentialInstance

        :param unicode username: The username for this credential.
        :param unicode password: The password will not be returned in the response.

        :returns: Newly created CredentialInstance
        :rtype: twilio.rest.api.v2010.account.sip.credential_list.credential.CredentialInstance