function mxVsdxConnect(connectElem) {
                        /**
                         * ID of edge
                         */
                        this.fromSheet = null;
                        /**
                         * ID of source
                         */
                        this.sourceToSheet = null;
                        /**
                         * Where connection is made to source
                         */
                        this.sourceToPart = -1;
                        /**
                         * ID of target
                         */
                        this.targetToSheet = null;
                        /**
                         * Where connection is made to target
                         */
                        this.targetToPart = -1;
                        this.fromCell = null;
                        this.endShape = null;
                        var fromSheet = connectElem.getAttribute(com.mxgraph.io.vsdx.mxVsdxConstants.FROM_SHEET);
                        this.fromSheet = (fromSheet != null && !(fromSheet.length === 0)) ? parseFloat(fromSheet) : -1;
                        var fromCell = connectElem.getAttribute(com.mxgraph.io.vsdx.mxVsdxConstants.FROM_CELL);
                        this.addFromCell(connectElem, fromCell);
                    }
Wrapper for connect element
See https://msdn.microsoft.com/en-us/library/office/ff768299%28v=office.14%29.aspx
@param {*} connectElem
@class