Template:Television channels and stations established or disestablished in year category/doc

Creates a category of the form
 * 1) "Television channels and stations established in YYYY", or
 * 2) Television channels and stations disestablished in YYYY"

... where YYYY is a 4-digit year.

e.g.
 * Category:Television channels and stations established in 1938 ✅
 * Category:Television channels and stations disestablished in 2003 ✅

Usage
No parameters needed

Errors
If the template is used on an invalid page, an error message is generated and the page is categorised in:
 * Category: (population: )

Errors include:


 * The page is not in the category namespace
 * The page's title does not take the form "Television channels and stations established in year" or "Television channels and stations disestablished in year"