Section 450.40. Appeal by people from trial order of dismissal

1.    An  appeal  by  the  people  from a trial order of dismissal, as
  authorized by subdivision two of section 450.20, may,  as  indicated  by
  section  290.10,  be  based either (a) upon the ground that the evidence
  adduced at the trial was legally sufficient  to  support  the  count  or
  counts  of the accusatory instrument dismissed by the order, or (b) upon
  the ground that, though not legally sufficient, such evidence would have
  been  legally  sufficient  had  the  court  not   erroneously   excluded
  admissible evidence offered by the people.
    2.   If the appeal is based upon the ground specified in paragraph (b)
  of subdivision one, and if  the  appellate  court  determines  that  the
  evidence  unsuccessfully  offered by the people was improperly excluded,
  and if at the trial the people made  on  offer  of  proof  with  respect
  thereto  pursuant  to subdivision three of section 290.10, the appellate
  court, in making its determination whether the people's  evidence  would
  have been legally sufficient had it not been for the improper exclusion,
  must  treat  the  excluded evidentiary matter as it is summarized in the
  offer of proof as evidence constituting a part of the people's case.