def annot(xcrd, ycrd, zcrd, txt, xancr='left'):
    """
    Annotation structure function for plotly
    :param xcrd: x position
    :param ycrd: y position
    :param zcrd: z position
    :param txt: annotation name
    :param xancr: anchor position
    :return: annotation as dict
    """
    annotation = dict(showarrow=False, x=xcrd, y=ycrd, z=zcrd, text=txt, xanchor=xancr, font=dict(color='white', size=12))
    return annotation