'Validate any of the provided parameters.'

def validate(self):

    super(ElasticIpAssociation, self).validate()
    eip = self.properties[self.EIP]
    allocation_id = self.properties[self.ALLOCATION_ID]
    instance_id = self.properties[self.INSTANCE_ID]
    ni_id = self.properties[self.NETWORK_INTERFACE_ID]
    if (bool(eip) == bool(allocation_id)):
        msg = _("Either    'EIP'    or    'AllocationId'    must    be    provided.")
        raise exception.StackValidationFailed(message=msg)
    if (eip and (not instance_id)):
        msg = _("Must    specify    'InstanceId'    if    you    specify    'EIP'.")
        raise exception.StackValidationFailed(message=msg)
    if ((not instance_id) and (not ni_id)):
        raise exception.PropertyUnspecifiedError('InstanceId', 'NetworkInterfaceId')
