Scrape daily wheat price data using Selenium and LXML

wheat.py

#!/usr/bin/python3
"""
Download wheat price data from http://agmarket.nic.in
Data is saved in file wheat.csv in current directory

Author: Jyotirmoy Bhattacharya, Ambedkar University, New Delhi, jyotirmoy@jyotirmoy.net
"""

from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support.select import Select
from selenium.common.exceptions import NoSuchElementException
from selenium.webdriver.common.by import By
from selenium.webdriver.support.wait import WebDriverWait
import selenium.webdriver.support.expected_conditions as EC
import calendar
import time
import lxml.html
import csv
import sys
from contextlib import closing

def get_agmarket_data(driver,year,month,state,commodity):
  driver.get("http://agmarknet.nic.in/agnew/NationalBEnglish/DatewiseCommodityReport.aspx?ss=2")
  yr = Select(driver.find_element_by_id("cboYear"))
  yr.select_by_visible_text(str(year))
  mn = Select(driver.find_element_by_id("cboMonth"))
  mn.select_by_visible_text(month)
  st = Select(driver.find_element_by_id("cboState"))
  st.select_by_visible_text(state)
  cm = Select(driver.find_element_by_id("cboCommodity"))
  cm.select_by_visible_text(commodity)
  driver.find_element_by_id("btnSubmit").click()
  recs =WebDriverWait(driver,10).until(
    EC.presence_of_element_located((By.ID,"gridRecords")))
  tbody = lxml.html.fragment_fromstring(recs.get_attribute("innerHTML"))
  last = None
  for row in tbody:
    i = 0
    maxc = len(last) if last is not None else 0
    nxt = []
    for e in row:
      t = e.text
      if not t and i<maxc:
        t = last[i]
      nxt.append(t)
      i += 1
    last = nxt
    yield nxt
    


if __name__=="__main__":
  with closing(webdriver.Firefox()) as driver, open("wheat.csv","w",newline='') as f:
    driver.implicitly_wait(5)
    writer = csv.writer(f)
    for state in ["Punjab","Maharashtra"]:
      for year in range(2010,2016):
        for month in calendar.month_name[1:]:
          try:
            res = "Success"
            writer.writerows(row
                             for row in get_agmarket_data(driver,
                                               year,month,state,"Wheat")
                             if row[0]!="Market" #Header row
                             )
          except NoSuchElementException:
            res = "Failed"
          print("{}: {}, {}, {}".format(res,state,year,month),file=sys.stderr)
          time.sleep(5)