def METHOD_NAME(self, group_node):
    """
    Finds Active viewer and
    place the node under it, also adds
    name of group into Input Process of the viewer
    Arguments:
        group_node (nuke node): nuke group node object
    """
    group_node_name = group_node["name"].value()
    viewer = [n for n in nuke.allNodes() if "Viewer1" in n["name"].value()]
    if len(viewer) > 0:
        viewer = viewer[0]
    else:
        msg = str("Please create Viewer node before you "
                  "run this action again")
        self.log.error(msg)
        nuke.message(msg)
        return None
    # get coordinates of Viewer1
    xpos = viewer["xpos"].value()
    ypos = viewer["ypos"].value()
    ypos += 150
    viewer["ypos"].setValue(ypos)
    # set coordinates to group node
    group_node["xpos"].setValue(xpos)
    group_node["ypos"].setValue(ypos + 50)
    # add group node name to Viewer Input Process
    viewer["input_process_node"].setValue(group_node_name)
    # put backdrop under
    create_backdrop(
        label="Input Process",
        layer=2,
        nodes=[viewer, group_node],
        color="0x7c7faaff"
    )
    return True