(1) A person's ignorance or mistake as to a matter of fact or law does not relieve him of criminal liability unless:
(a) Such ignorance or mistake negatives the existence of the culpable mental state required for commission of an offense; or (b) The statute under which he is charged or a statute related thereto expressly provides that such ignorance or mistake constitutes a defense or exemption; or (c) Such ignorance or mistake is of a kind that supports a defense of justification as defined in this Penal Code.
(2) When ignorance or mistake relieves a person of criminal liability under subsection (1) but he would be guilty of another offense had the situation been as he supposed it was, he may be convicted of that other offense.
(3) A person's mistaken belief that his conduct, as a matter of law, does not constitute an offense does not relieve him of criminal liability, unless such mistaken belief is actually founded upon an official statement of the law, afterward determined to be invalid or erroneous, contained in:
(a) A statute or other enactment; or (b) A judicial decision, opinion or judgment; or (c) An administrative order or grant of permission; or (d) An official interpretation of the public officer or body charged by law with responsibility for the interpretation, administration or enforcement of the law defining the offense.