Section 450.30. Appeal from sentence

1.    An  appeal  by  the  defendant from a sentence, as authorized by
  subdivision two of section 450.10, may be based  upon  the  ground  that
  such sentence either was (a) invalid as a matter of law, or (b) harsh or
  excessive.    A sentence is invalid as a matter of law not only when the
  terms thereof are unauthorized  but  also  when  it  is  based  upon  an
  erroneous   determination  that  the  defendant  had  a  previous  valid
  conviction for an offense or, in the case of a  resentence  following  a
  revocation  of a sentence of probation or conditional discharge, upon an
  improper  revocation  of  such  original  sentence.  An  appeal  by  the
  defendant from a sentence, as authorized by subdivision three of section
  450.15,  may  be  based  upon the ground that such sentence was harsh or
  excessive.
    2.   An appeal by  the  people  from  a  sentence,  as  authorized  by
  subdivision  four  of  section 450.20, may be based only upon the ground
  that such sentence was invalid as a matter of law.
    3.  An appeal from a sentence, within the meaning of this section  and
  sections  450.10  and  450.20,  means an appeal from either the sentence
  originally imposed or from a resentence following an order vacating  the
  original sentence.  For purposes of appeal, the judgment consists of the
  conviction  and the original sentence only, and when a resentence occurs
  more than thirty days after the original sentence, a defendant  who  has
  not previously filed a notice of appeal from the judgment may not appeal
  from the judgment, but only from the resentence.
    4.    When  as  a  result  of a successful appeal by the people from a
  sentence, the defendant receives a resentence the  terms  of  which  are
  more  severe  than  those  of  the  original  or  reversed sentence, the
  defendant, if he has not taken an appeal from the  judgment,  may,  even
  though  the  period  for  doing  so  as prescribed in section 460.10 has
  expired, take such an appeal by filing and serving a notice  of  appeal,
  or  an  affidavit of errors as the case may be, within thirty days after
  imposition of the resentence.  Upon such an appeal, only the  conviction
  is  reviewable;  and  any  appellate challenge to the resentence must be
  made upon a separate appeal therefrom.