import re


def is_internal(message):
    """ Checks to see if a message is internal to Enron """
    enron_re = re.compile('@enron.com')
    if not enron_re.search(message.sender):
        return False
    if len(message.recipients) == 0:
        return False
    return all(r for r in message.recipients if enron_re.search(r))