code: def fexist(self, fields):
          
  
          if type(fields) in [tuple, list]:
              str = ','.join(fields)
          else:
              str = fields
          ret = _C.VSfexist(self._id, str)
          if ret < 0:
              return 0
          else:
              return 1
docs: Check if a vdata contains a given set of fields.
  
          Args::
  
            fields   sequence of field names whose presence in the
                     vdata must be checked
  
          Returns::
  
            true  (1) if the given fields are present
            false (0) otherwise
  
          C library equivalent : VSfexist