def validate_name names, levels
      error_msg = "'names' and 'levels' should be of same size. Size of the "\
      "'name' array is #{names.size} and size of the MultiIndex 'levels' and "\
      "'labels' is #{labels.size}."
      suggestion_msg = "If you don\'t want to set name for particular level " \
      "(say level 'i') then put empty string on index 'i' of the 'name' Array."

      raise SizeError, error_msg if names.size > levels.size
      raise SizeError, [error_msg, suggestion_msg].join("\n") if names.size < levels.size
    end
Array `name` must have same length as levels and labels.