Context component:

    topology_uuids : Set[str] = set()

    related_topologies : List[Dict] = list()

    link_endpoints_data : List[Dict] = list()

    for endpoint_id in request.link_endpoint_ids:

    for i,endpoint_id in enumerate(request.link_endpoint_ids):

        endpoint_topology_uuid, _, endpoint_uuid = endpoint_get_uuid(

            endpoint_id, allow_random=False)

        link_endpoints_data.append({

            'link_uuid'    : link_uuid,

            'endpoint_uuid': endpoint_uuid,

            'position'     : i,

        })

        if endpoint_topology_uuid not in topology_uuids:

# See the License for the specific language governing permissions and

# limitations under the License.

from sqlalchemy import Column, DateTime, ForeignKey, String

import operator

from sqlalchemy import CheckConstraint, Column, DateTime, ForeignKey, Integer, String

from sqlalchemy.dialects.postgresql import UUID

from sqlalchemy.orm import relationship

from typing import Dict

            'name'             : self.link_name,

            'link_endpoint_ids': [

                link_endpoint.endpoint.dump_id()

                for link_endpoint in self.link_endpoints

                for link_endpoint in sorted(self.link_endpoints, key=operator.attrgetter('position'))

            ],

        }

    link_uuid     = Column(ForeignKey('link.link_uuid',         ondelete='CASCADE' ), primary_key=True)

    endpoint_uuid = Column(ForeignKey('endpoint.endpoint_uuid', ondelete='RESTRICT'), primary_key=True, index=True)

    position      = Column(Integer, nullable=False)

    link     = relationship('LinkModel',     back_populates='link_endpoints', lazy='joined')

    endpoint = relationship('EndPointModel', lazy='joined') # back_populates='link_endpoints'

    __table_args__ = (

        CheckConstraint(position >= 0, name='check_position_value'),

    )