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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 is_email(potential_email_address):
 """ Check if potential_email_address is a valid e-mail address. Please note that this function has no false-negatives but many false-positives. So if it returns that the input is not a valid e-mail adress, it certainly isn't. If it returns True, it might still be invalid. For example, the domain could not be registered. Parameters potential_email_address : str Returns ------- is_email : bool Examples -------- False True True False False """

    context, mail = parseaddr(potential_email_address)
    first_condition = len(context) == 0 and len(mail) != 0
    dot_after_at = ('@' in potential_email_address and
                    '.' in potential_email_address.split('@')[1])
    return first_condition and dot_after_at