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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 get_cert_builder(expires):
 """Get a basic X509 cert builder object. Parameters expires : datetime When this certificate will expire. """

    now = datetime.utcnow().replace(second=0, microsecond=0)

    if expires is None:
        expires = get_expires(expires, now=now)
    expires = expires.replace(second=0, microsecond=0)

    builder = x509.CertificateBuilder()
    builder = builder.not_valid_before(now)
    builder = builder.not_valid_after(expires)
    builder = builder.serial_number(x509.random_serial_number())

    return builder