2.3 Built-in Types
The following sections describe the standard types that are built into the interpreter.
Historically, Python's built-in types have differed from user-defined types because it was
not possible to use the built-in types as the basis for object-oriented inheritance. With
the 2.2 release this situation has started to change, although the intended unification of
user-defined and built-in types is as yet far from complete.
The principal built-in types are numerics, sequences, mappings, files classes,
instances and exceptions.
Some operations are supported by several object types; in particular, all objects can
be compared, tested for truth value, and converted to a string (with the
notation). The latter conversion is implicitly used when an object is written by the print
statement. (Information on print statement and other language statements can be found in the
Reference Manual and the Python Tutorial.)