Section 179.00. Model forms of obligations

The model form of a coupon bond
  and the model form of a note payable to bearer contained in  schedule  B
  annexed  hereto  may be used, but this section shall not be construed to
  prevent or invalidate the use of other forms in lieu  thereof.  Both  of
  such  forms  provide  for  the  conversion  of  the  obligation  into  a
  registered obligation  and  also  contain  a  provision  permitting  the
  redemption  of  the  obligation  prior  to maturity by the municipality,
  school district or district corporation issuing such obligation.