import os
import csv
import xlrd

with xlrd.open_workbook('Pilvetyybid_1968_Jõgeva.xls') as wb:
    sh = wb.sheet_by_index(0)  # or wb.sheet_by_name('name_of_the_sheet_here')
    with open('a_file.csv', 'w', newline='') as f:
        spamwriter = csv.writer(f, delimiter=';')
        c = csv.writer(f)

        for row in range(sh.nrows):
            #for col in range(sh.ncols):
            c.writerow(sh.row_values(row))