Path transitions in d3

Question

wb=openpyxl.load_workbook('simpleCoordinate.xlsx')
sheet=wb.get_sheet_by_name('Sheet1')

from collections import defaultdict

coordinate_list = list()
for i in range (1,201,1):
    coordinate_list += [(sheet.cell(row=i,column=1).value, sheet.cell(row=i,     column=2).value)]

coord_dict = defaultdict(list)
for oid, xy in coordinate_list:
    coord_dict[oid] = xy

print(list(coord_dict.items()))

The transition does not take place. Any pointers to where Im going wrong?