public boolean removeChild( PlanNode child ) {
        boolean result = this.children.remove(child);
        if (result) {
            child.parent = null;
        }
        return result;
    }
public boolean removeChild ( PlanNode child ) { boolean result = this . children . remove ( child ) ; if ( result ) { child . parent = null ; } return result ; }
Remove the node from this node.

@param child the child node; may not be null
@return true if the child was removed from this node, or false if the supplied node was not a child of this node