NOTE: need to move this elsewhere. It's hard to provide a good coverage of built-ins in this context.
Python defines many builtin functions that are usable straightaway. e.g.
In [5]:
print int("10")
print hex(10)
print bin(10)
type() is another builtin, it returns the type of the symbol passed to it.
"print" itself is a built-in ! The status of print is rather complicated in python - it's actually not a function!