code: def fdefine(self, name, type, order):
          
  
          _checkErr('fdefine', _C.VSfdefine(self._id, name, type, order),
                    'cannot define field')
docs: Define a field. To initialize a newly created vdata with
          fields created with fdefine(), assign a tuple of field names
          to the _fields attribute or call the setfields() method.
  
          Args::
  
            name     field name
            type     field data type (one of HC.xxx)
            order    field order (number of values in the field)
  
          Returns::
  
            None
  
          C library equivalent : VSfdefine