'Updates this Credential instance
:param sid: Credential instance identifier
:param credential_type: Credential type
:param friendly_name: Credential\'s friendly name
:param certificate: Credential\'s certificate
:param private_key: Credential\'s Private key
:param sandbox: Credential\'s Sandbox
:param api_key: Credential\'s Api Key
:return: Updated instance'

def update(self, credential_type, **kwargs):

    kwargs['type'] = credential_type
    return self.update_instance(**kwargs)
