curl -i -X POST "https://api.box.com/2.0/retention_policy_assignments" \
     -H "authorization: Bearer <ACCESS_TOKEN>" \
     -H "content-type: application/json" \
     -d '{
       "policy_id": "173463",
       "assign_to": {
         "type": "folder",
         "id": "6564564"
       }
     }'

client.retention_policy_assignments.create_retention_policy_assignment(
    retention_policy.id,
    CreateRetentionPolicyAssignmentAssignTo(
        type=CreateRetentionPolicyAssignmentAssignToTypeField.FOLDER, id=folder.id
    ),
)

await client.retentionPolicyAssignments.createRetentionPolicyAssignment({
  policyId: retentionPolicy.id,
  assignTo: {
    type: 'folder' as CreateRetentionPolicyAssignmentRequestBodyAssignToTypeField,
    id: folder.id,
  } satisfies CreateRetentionPolicyAssignmentRequestBodyAssignToField,
} satisfies CreateRetentionPolicyAssignmentRequestBody);

try await client.retentionPolicyAssignments.createRetentionPolicyAssignment(requestBody: CreateRetentionPolicyAssignmentRequestBody(policyId: retentionPolicy.id, assignTo: CreateRetentionPolicyAssignmentRequestBodyAssignToField(type: CreateRetentionPolicyAssignmentRequestBodyAssignToTypeField.folder, id: folder.id)))

client.getRetentionPolicyAssignments().createRetentionPolicyAssignment(new CreateRetentionPolicyAssignmentRequestBody(retentionPolicy.getId(), new CreateRetentionPolicyAssignmentRequestBodyAssignToField.Builder(CreateRetentionPolicyAssignmentRequestBodyAssignToTypeField.FOLDER).id(folder.getId()).build()))

await client.RetentionPolicyAssignments.CreateRetentionPolicyAssignmentAsync(requestBody: new CreateRetentionPolicyAssignmentRequestBody(policyId: retentionPolicy.Id, assignTo: new CreateRetentionPolicyAssignmentRequestBodyAssignToField(type: CreateRetentionPolicyAssignmentRequestBodyAssignToTypeField.Folder) { Id = folder.Id }));

{
  "id": "11446498",
  "type": "retention_policy_assignment",
  "retention_policy": {
    "id": "12345",
    "type": "retention_policy",
    "policy_name": "Some Policy Name",
    "retention_length": "365",
    "disposition_action": "permanently_delete",
    "max_extension_length": "365"
  },
  "assigned_to": {
    "id": "a983f69f-e85f-4ph4-9f46-4afdf9c1af65",
    "type": "metadata_template"
  },
  "filter_fields": [
    {
      "field": "a0f4ee4e-1dc1-4h90-a8a9-aef55fc681d4",
      "value": "0c27b756-0p87-4fe0-a43a-59fb661ccc4e"
    }
  ],
  "assigned_by": {
    "id": "11446498",
    "type": "user",
    "name": "Aaron Levie",
    "login": "ceo@example.com"
  },
  "assigned_at": "2012-12-12T10:53:43-08:00",
  "start_date_field": "upload_date"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}

{
  "type": "error",
  "status": 400,
  "code": "item_name_invalid",
  "message": "Method Not Allowed",
  "context_info": {
    "message": "Something went wrong"
  },
  "help_url": "https://developer.box.com/guides/api-calls/permissions-and-errors/common-errors/",
  "request_id": "abcdef123456"
}