It is not innocent but calculated purveyance which is prohibited. This act shall not apply to any persons who may possess or distribute obscene matter or participate in conduct otherwise proscribed by this act when such possession, distribution, or conduct occurs:
If this issue is not presented by the prosecution’s evidence, the defendant may raise the same as an affirmative defense by presenting some evidence thereon. Where raised, the prosecution must sustain the burden of proving the defendant guilty beyond a reasonable doubt as to that issue.