unable to find post button

"post_button = driver.find_element_by_xpath("//*[@data-testid='react-composer-post-button']")
clickable = False
while not clickable:
cursor = post_button.find_element_by_tag_name('span').value_of_css_property("cursor")
if cursor == "pointer":
clickable = True
break
post_button.click()
time.sleep(5)"

Exception -

---------------------------------------------------------------------------
ElementNotVisibleException Traceback (most recent call last)
in
16 clickable = True
17 break
---> 18 post_button.click()
19 time.sleep(5)