code: def convertToDatetime(fmt="%Y-%m-%dT%H:%M:%S.%f"):
          
          def cvt_fn(s,l,t):
              try:
                  return datetime.strptime(t[0], fmt)
              except ValueError as ve:
                  raise ParseException(s, l, str(ve))
          return cvt_fn
docs: Helper to create a parse action for converting parsed
          datetime string to Python datetime.datetime
  
          Params -
           - fmt - format to be passed to datetime.strptime (default= ``"%Y-%m-%dT%H:%M:%S.%f"``)
  
          Example::
  
              dt_expr = pyparsing_common.iso8601_datetime.copy()
              dt_expr.setParseAction(pyparsing_common.convertToDatetime())
              print(dt_expr.parseString("1999-12-31T23:59:59.999"))
  
          prints::
  
              [datetime.datetime(1999, 12, 31, 23, 59, 59, 999000)]