How to use the @jupyterlab/docregistry.MimeContent function in @jupyterlab/docregistry

it('should require options', () => {
        const renderer = RENDERMIME.createRenderer('text/markdown');
        const widget = new MimeContent({
          context: dContext,
          renderer,
          mimeType: 'text/markdown',
          renderTimeout: 1000,
          dataType: 'string'
        });
        expect(widget).to.be.an.instanceof(MimeContent);
      });
    });

it('should require options', () => {
        const renderer = RENDERMIME.createRenderer('text/markdown');
        const widget = new MimeContent({
          context: dContext,
          renderer,
          mimeType: 'text/markdown',
          renderTimeout: 1000,
          dataType: 'string'
        });
        expect(widget).to.be.an.instanceof(MimeContent);
      });
    });