from ironxl import *

# Load an existing WorkSheet
workbook = WorkBook.Load("sample.xls")
worksheet = workbook.WorkSheets[0]

# Set data display format to range
worksheet["A3"].Value = DateTime(2020, 1, 1, 12, 12, 12)
worksheet["A4"].Value = DateTime(2022, 3, 3, 10, 10, 10)
worksheet["A5"].Value = DateTime(2021, 2, 2, 11, 11, 11)

selected_range = worksheet["A3:A5"]

# The cell(A3) value will look like 1/1/2020 12:12:12 PM
selected_range.FormatString = "MM/dd/yy h:mm:ss"

# Save changes with applied number formats
workbook.SaveAs("numberFormats.xls")