'Perform a specialized doctest.'

def custom_doctest(self, decorator, input_lines, found, submitted):

    from .custom_doctests import doctests
    args = decorator.split()
    doctest_type = args[1]
    if (doctest_type in doctests):
        doctests[doctest_type](self, args, input_lines, found, submitted)
    else:
        e = 'Invalid    option    to    @doctest:    {0}'.format(doctest_type)
        raise Exception(e)
