Can't add text to input type="tel" inside an IFrame using Selenium Python

HTML

I'm trying to write into "Security Code"

EDIT HTML CODE

I tried to write this:

CVXPATH = '//input[@type="tel"]' cv=driver.find_element_by_xpath(CVXPATH) cv.send_keys("000")

But I have this error:

line 242, in check_response 
raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.ElementNotInteractableException: Message: element not interactable

How can I solve this?