Subtract boolean from float in python -

this question has answer here:

anyways when debuging code found statement subtracted boolean float.

then tried following in python console:

>>> 15.0 - true  14.0 >>> 15.0 - false 15.0

can explain me:

why subtracting booleans numeric types legal (the docs state can and, not , or on boolean values: http://docs.python.org/3/library/stdtypes.html#boolean-operations-and-or-not)
has practical use?

http://docs.python.org/3/library/stdtypes.html#boolean-values

boolean values 2 constant objects false , true. used represent truth values (although other values can considered false or true).

in numeric contexts (for example when used argument arithmetic operator), behave integers 0 , 1, respectively.
not nowadays, can write

result = numeric_value * a_bool (this 1 used lot, example, in shader languages)

instead of

result = numeric_value if a_bool else 0

or

result = (value_if_false, value_if_true)[a_bool]

don't of though.

it's people experience in lower-level languages expect, why take away them? in c, true , false still macros 1 , 0.

before 2.3, there no bool type in python well, when introduced making subclass of int made sure no code broken.

Brazell