code: def _validate_volumes(input_volumes):
      '''Check input_volumes contains a valid list of volumes.
  
      Parameters
      ----------
      input_volumes : list
          list of volume values. Castable to numbers.
  
      '''
      if not (input_volumes is None or isinstance(input_volumes, list)):
          raise TypeError("input_volumes must be None or a list.")
  
      if isinstance(input_volumes, list):
          for vol in input_volumes:
              if not core.is_number(vol):
                  raise ValueError(
                      "Elements of input_volumes must be numbers: found {}"
                      .format(vol)
                  f _validate_volumes(input_volumes):
      '''Check input_volumes contains a valid list of volumes.
  
      Parameters
      ----------
      input_volumes : list
          list of volume values. Castable to numbers.
  
      '''
      if not (input_volumes is None or isinstance(input_volumes, list)):
          raise TypeError("input_volumes must be None or a list.")
  
      if isinstance(input_volumes, list):
          for vol in input_volumes:
              if not core.is_number(vol):
                  raise ValueError(
                      "Elements of input_volumes must be numbers: found {}"
                      .format(vol)
                  )
docs: Check input_volumes contains a valid list of volumes.
  
      Parameters
      ----------
      input_volumes : list
          list of volume values. Castable to numbers.