Lists assignments. Only explicitly created assignments will be returned. Example: * Organization organizationA contains two projects, project1 and project2. * Reservation res1 exists and was created previously. * CreateAssignment was used previously to define the following associations between entities and reservations: and In this example, ListAssignments will just return the above two assignments for reservation res1, and no expansion/merge will happen. The wildcard "-" can be used for reservations in the request. In that case all assignments belongs to the specified project and location will be listed. Note "-" cannot be used for projects nor locations.