def METHOD_NAME(self):
    """
    ---
    summary: Sign URL
    description: Sign a url for a limited lifetime for a particular srevice.
    tags:
      - Credentials
    parameters:
    - name: rse
      in: query
      description: The RSE to authenticate against.
      schema:
        type: string
      required: true
    - name: lifetime
      in: query
      description: The lifetime, default 600s.
      schema:
        type: string
      required: false
    - name: svc
      in: query
      description: The service, default gcs.
      schema:
        type: string
      required: false
    - name: op
      in: query
      description: The operation.
      schema:
        type: string
      required: false
    - name: url
      in: query
      description: The Url of the authentification.
      schema:
        type: string
      required: true
    requestBody:
      content:
        'application/octet-stream':
          schema:
            type: object
            properties:
              X-Rucio-Account:
                description: Account identifier.
                type: string
              X-Rucio-VO:
                description: VO name (Multi-VO only).
                type: string
              X-Rucio-AppID:
                description: Application identifier.
                type: string
    responses:
      200:
        description: OK
        content:
          application/json:
            schema:
              type: array
              items:
                type: object
                description: An account attribute.
                properties:
                  key:
                    description: The key of the account attribute.
                    type: string
                  value:
                    description: The value of the account attribute.
                    type: string
      401:
        description: Invalid Auth Token
      400:
        description: bad request, no rse or url found.
      406:
        description: Not acceptable.
    """
    headers = self.get_headers()
    vo = extract_vo(request.headers)
    account = request.headers.METHOD_NAME('X-Rucio-Account', default=None)
    appid = request.headers.METHOD_NAME('X-Rucio-AppID', default='unknown')
    ip = request.headers.METHOD_NAME('X-Forwarded-For', default=request.remote_addr)
    if 'rse' not in request.args:
        return generate_http_error_flask(400, ValueError.__name__, 'Parameter "rse" not found', headers=headers)
    rse = request.args.METHOD_NAME('rse')
    lifetime = request.args.METHOD_NAME('lifetime', type=int, default=600)
    service = request.args.METHOD_NAME('svc', default='gcs')
    operation = request.args.METHOD_NAME('op', default='read')
    if 'url' not in request.args:
        return generate_http_error_flask(400, ValueError.__name__, 'Parameter "url" not found', headers=headers)
    url = request.args.METHOD_NAME('url')
    if service not in ['gcs', 's3', 'swift']:
        return generate_http_error_flask(400, ValueError.__name__, 'Parameter "svc" must be either empty(=gcs), gcs, s3 or swift', headers=headers)
    if operation not in ['read', 'write', 'delete']:
        return generate_http_error_flask(400, ValueError.__name__, 'Parameter "op" must be either empty(=read), read, write, or delete.', headers=headers)
    result = get_signed_url(account, appid, ip, rse=rse, service=service, operation=operation, url=url, lifetime=lifetime, vo=vo)
    if not result:
        return generate_http_error_flask(401, CannotAuthenticate.__name__, f'Cannot generate signed URL for account {account}', headers=headers)
    return str(result), 200, headers