'Return spec for creating backing with a single disk.
:param name: name of the backing
:param size_kb: disk size in KB
:param disk_type: disk provisioning type
:param ds_name: datastore name where the disk is to be provisioned
:param profile_id: storage policy profile identification
:param adapter_type: disk adapter type
:param extra_config: key-value pairs to be written to backing\'s
extra-config
:return: spec for creation'

def get_create_spec(self, name, size_kb, disk_type, ds_name, profile_id=None, adapter_type='lsiLogic', extra_config=None):

    create_spec = self._get_create_spec_disk_less(name, ds_name, profileId=profile_id, extra_config=extra_config)
    create_spec.deviceChange = self._create_specs_for_disk_add(size_kb, disk_type, adapter_type, profile_id)
    return create_spec
