def extract_email_addresses(emails, sep=","):
    """
    Transforms a string of multiple email adresses (separated by commas) into a list
    :param str emails: Single string of emails separated by a specific character
    :param str sep: The separator used in the emails parameter. Defaults to ','
    :return: A list of email addresses
    :rtype: list(str)
    """
    if type(emails) == str:
        emails = emails.split(",")
        emails = list(map(lambda x: x.strip(), emails))
    return emails