try:
    from .qt import QtGui as _QtGui
except ImportError as e:
    raise ImportError('Viewer requires Qt')

from .viewers import ImageViewer, CollectionViewer

import warnings
try:
    from .viewers import ImageViewer, CollectionViewer
except ImportError as e:
    warnings.warn('Viewer requires Qt')

Allow viewer package to import without Qt
Allow viewer package to import without Qt
