def get_geometry(dataset):
    """
    Extract and return geometry coordinates as a list in a dictionary:
    returns
    {
      'geometry': {
                    'type' : 'Polygon',
                    'coordinates': [...]
                  }
    }
    or
    empty dictionary
    """

    valid_data = dataset._gs.get('valid_data')

    return {'geometry': valid_data} if valid_data else dict()