docstr: Define the conversion from item value to displayed text. 
  
  If a string is specified, it is used as a format string for converting
  float values (and all other types are converted using str). If a 
  function is specified, it will be called with the item as its only
  argument and must return a string.
  
  Added in version 0.9.9.
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code: def setFormat(self, fmt):
      """Define the conversion from item value to displayed text.
  
      If a string is specified, it is used as a format string for converting
      float values (and all other types are converted using str). If a
      function is specified, it will be called with the item as its only
      argument and must return a string.
  
      Added in version 0.9.9.
      """
      if (
          fmt is not None
          and not isinstance(fmt, str)
          and not callable(fmt)
      ):
          raise ValueError(
              "Format argument must string, callable, or None. (got %s)"
              % fmt
          )
      self._format = fmt
      self._updateText()
  
imports: import numpy
  from ..Qt import QtCore, QtGui, QtWidgets
label_desc: Use image node_id 4 for calling the TableWidgetItem obj's underlying member method code with example usage: obj.setFormat(fmt) without return types