import os
import csv
import xlrd
import xlwt

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', 'wb') as f:
        c = csv.writer(f)
        for col in range(sh.ncols):
            if col ==0 or col>10:
                pass
            else:
                for row in range(sh.nrows):
                    if row == 0:
                        pass
                else:
                    c.writerow(sh.row_values(row))

    c.writerow(sh.row_values(row))
TypeError: a bytes-like object is required, not 'str'