Disable contracts on production

If you want disable contracts on production, pass debug=True to decorator:

@deal.post(lambda x: x > 0, debug=True)
def my_sum(*args):
    return sum(args)

If you run Python with -O option, contracts will be disabled. This is uses Python’s __debug__ option:

The built-in variable __debug__ is True under normal circumstances, False when optimization is requested (command line option -O).

Also, you can explicitly enable or disable contracts:

# disable contracts without `debug=True`

# enable contracts with `debug=True`

# disable contracts with `debug=True`

# disable all contracts
deal.switch(main=False, debug=False)

# return default behavior
# (`main` enabled, `debug` the same as `__debug__`)