Display the specified annotations.
        :param anns (array of object): annotations to display
        :return: None

def showAnns(self, anns):
        """
        Display the specified annotations.
        :param anns (array of object): annotations to display
        :return: None
        """
        if len(anns) == 0:
            return 0
        if 'segmentation' in anns[0] or 'keypoints' in anns[0]:
            datasetType = 'instances'
        elif 'caption' in anns[0]:
            datasetType = 'captions'
        else:
            raise Exception('datasetType not supported')
        if datasetType == 'instances':
            ax = plt.gca()
            ax.set_autoscale_on(False)
            polygons = []
            color = []
            for ann in anns:
                c = (np.random.random((1, 3))*0.6+0.4).tolist()[0]
                if 'segmentation' in ann:
                    if type(ann['segmentation']) == list:
                        # polygon
                        for seg in ann['segmentation']:
                            poly = np.array(seg).reshape((int(len(seg)/2), 2))
                            polygons.append(Polygon(poly))
                            color.append(c)
                    else:
                        # mask
                        t = self.imgs[ann['image_id']]
                        if type(ann['segmentation']['counts']) == list:
                            rle = maskUtils.frPyObjects([ann['segmentation']], t['height'], t['width'])
                        else:
                            rle = [ann['segmentation']]
                        m = maskUtils.decode(rle)
                        img = np.ones( (m.shape[0], m.shape[1], 3) )
                        if ann['iscrowd'] == 1:
                            color_mask = np.array([2.0,166.0,101.0])/255
                        if ann['iscrowd'] == 0:
                            color_mask = np.random.random((1, 3)).tolist()[0]
                        for i in range(3):
                            img[:,:,i] = color_mask[i]
                        ax.imshow(np.dstack( (img, m*0.5) ))
                if 'keypoints' in ann and type(ann['keypoints']) == list:
                    # turn skeleton into zero-based index
                    sks = np.array(self.loadCats(ann['category_id'])[0]['skeleton'])-1
                    kp = np.array(ann['keypoints'])
                    x = kp[0::3]
                    y = kp[1::3]
                    v = kp[2::3]
                    for sk in sks:
                        if np.all(v[sk]>0):
                            plt.plot(x[sk],y[sk], linewidth=3, color=c)
                    plt.plot(x[v>0], y[v>0],'o',markersize=8, markerfacecolor=c, markeredgecolor='k',markeredgewidth=2)
                    plt.plot(x[v>1], y[v>1],'o',markersize=8, markerfacecolor=c, markeredgecolor=c, markeredgewidth=2)
            p = PatchCollection(polygons, facecolor=color, linewidths=0, alpha=0.4)
            ax.add_collection(p)
            p = PatchCollection(polygons, facecolor='none', edgecolors=color, linewidths=2)
            ax.add_collection(p)
        elif datasetType == 'captions':
            for ann in anns:
                print(ann['caption'])