code: def isFieldValid(self, row, field):
          
          param = self._parameters[row]
          if param['parameter'] == '':
              return False
          if field == 'nsteps':
              return self.numSteps(row) != 0
          if param['parameter'] == 'filename':
              # do something here... check filenames?
              return True
          if field == 'parameter':
              return True
          # else check that value is between min and max allowed
          return self.checkLimits(row, param[field])
docs: Verifies the value in *field* for parameter at index 
          *row*
  
          :param row: the ith parameter number
          :type row: int
          :param field: detail of the parameter to check
          :type field: str
          :returns: bool -- True if valid