def trigger_segments_severance(self, pos):
        """Prep to cut existing line segments.

        Parameters
        ==========
        pos (2-tuple of integers)
            start point of "cut" line segment used to define
            which segments must be severed.
        """
        ### store cut start position
        self.cut_start_pos = pos

        ### change window manager state to draw temporary
        ### "cut" line between provided cut start position
        ### and mouse
        APP_REFS.wm.set_state("segment_severance")

        ### restart the loop
        raise ContinueLoopException
Prep to cut existing line segments.

        Parameters
        ==========
        pos (2-tuple of integers)
            start point of "cut" line segment used to define
            which segments must be severed.
        
nodezator/graphman/socketparenthood/action.py