Selenium script to log in to Facebook and post on wall

Selenium_Python_Fb_Wall_Poster

from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from time import sleep
from selenium.common.exceptions import TimeoutException
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support.ui import Select
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions
from selenium.common.exceptions import NoSuchElementException
 
driver = webdriver.Firefox()
driver.get('https://www.facebook.com/')
print "Opened facebook..."
a = driver.find_element_by_id('email')
a.send_keys('Your email id')
print "Email Id entered..."
b = driver.find_element_by_id('pass')
b.send_keys('Your password')
print "Password entered..."
c = driver.find_element_by_id('loginbutton')
c.click()
driver.get("https://www.facebook.com/apoorvu")
post_box=driver.find_element_by_xpath("//*[@name='xhpc_message']")
post_box.click()
post_box.send_keys("Testing using Name not ID.Selenium is easy.")
sleep(2)
post_it=driver.find_element_by_xpath("//*[@id='u_0_1a']/div/div[6]/div/ul/li[2]/button")
post_it.click()
print "Posted..."

I have the same error with Can't locate item: {"method": "xpath", "selector": "// * [@ name = 'xhpc_message_text']"}
is to create a publication in the group someone I can solve who can help me
Unable to locate element: {"method":"xpath","selector":"//*[@name='xhpc_message_text']"}