Celsius to Fahrenheit

The shop's freezer shows temperatures in Celsius, but the supplier's paperwork uses Fahrenheit. Write to_fahrenheit(c) that converts. The formula is c * 9 / 5 + 32.

to_fahrenheit(0)    ->  32.0
to_fahrenheit(100)  ->  212.0
to_fahrenheit(10)   ->  50.0

Some inputs give long decimals, such as to_fahrenheit(-18) printing -0.3999999999999986 rather than -0.4. That is how computers store decimal numbers, and the checks allow for it.

def to_fahrenheit(c):
    ...