Section 54. Age requirements

Notwithstanding  any provision of law to the
  contrary, except as herein provided, neither  the  state  civil  service
  department  nor  the  state  civil service commission, nor any municipal
  civil  service  commission  shall  prohibit,  prevent,  disqualify,   or
  discriminate   against,  any  person  who  is  physically  and  mentally
  qualified, from participating in a civil  service  examination  or  from
  qualifying  for  a position in the classified civil service, or penalize
  any such person in a final rating by reason of his or her age;  and  any
  such  rule, requirement, resolution, regulation or penalization shall be
  void. Nothing herein contained, however, shall prevent the  adoption  of
  reasonable  minimum  or  maximum  age  requirements for open competitive
  examinations for positions where it is determined by the department  and
  approved   by  the  commission  that  such  age  requirements  would  be
  reasonable  minimum  qualification  for  such  position.   Minimum   age
  requirements  shall  in  no case prohibit an applicant who is within six
  months of the  minimum  age  requirement  from  taking  any  competitive
  examination. Nothing herein contained shall be construed to prohibit the
  disqualification, on account of age, of any applicant for a position who
  has  reached  the  mandatory  retirement  age  applicable by law to such
  position.