execution environment interpreter options and environment interactive sessions xi launching python applications site configuration files per-user site packages enabling future features program termination testingdebuggingprofilingand tuning documentation strings and the doctest module unit testing and the unittest module the python debugger and the pdb module debugger commands debugging from the command line configuring the debugger program profiling tuning and optimization making timing measurements making memory measurements disassembly tuning strategies iithe python library built-in functions and exceptions built-in functions and types built-in exceptions exception base classes exception instances predefined exception classes built-in warnings future_builtins python runtime services atexit copy notes lib fl ff