choice(argument, values)
Directive option utility function, supplied to enable options whose argument must be a member of a finite set of possible values (must be lower case). A custom conversion function must be written to use it. For example:
from docutils.parsers.rst import directives def yesno(argument): return directives.choice(argument, ('yes', 'no'))
Raise ValueError if no argument is found or if the argument's value is not valid (not an entry in the supplied list).