license is a built-in name in Python's interactive interpreter, provided by the site module. Typing it in a REPL prints a short notice and instructs you to call license() to read the full text.
>>> license
Type license() to see the full license text
>>> license()
A. HISTORY OF THE SOFTWARE
==========================
...
It is not a reserved keyword (unlike return or class), so you can technically shadow it with an assignment, but doing so silently breaks the built-in. The same applies to copyright and credits, which are also injected by site at startup.