How to reset the row number (row=0) in tkinter.treeview?

[godisreal]

When I open the first csv data file, the row number starts from zero, and everything seems to be OK. However, when I open the second csv file, and row number accumulates, but does not restart from zero. Why? Anyone knows the solution to this problem in tkinter.treeview ?

column= treeviewA.identify_column(event.x)# column
row = treeviewA.identify_row(event.y)  # row

cn = int(str(column).replace('#',''))
rn = int(str(row).replace('I',''), base=16)

print("cn:", column, cn)
print("rn:", row, rn)