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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def parse_emails(emails):
 """ A function that returns a list of valid email addresses. This function will also convert a single email address into a list of email addresses. None value is also converted into an empty list. """


    if isinstance(emails, string_types):
        emails = [emails]
    elif emails is None:
        emails = []

    for email in emails:
        try:
            validate_email_with_name(email)
        except ValidationError:
            raise ValidationError('%s is not a valid email address' % email)

    return emails