'Number of local workers to run, a strictly positive integer.'

def opt_jobs(self, number):

    try:
        number = int(number)
    except ValueError:
        raise usage.UsageError(("Expecting    integer    argument    to    jobs,    got    '%s'" % number))
    if (number <= 0):
        raise usage.UsageError('Argument    to    jobs    must    be    a    strictly    positive    integer')
    self['jobs'] = number
