code: def setParseAction( self, *fns, **kwargs ):
          
          self.parseAction = list(map(_trim_arity, list(fns)))
          self.callDuringTry = ("callDuringTry" in kwargs and kwargs["callDuringTry"])
          return self
docs: Define action to perform when successfully matching parse element definition.
             Parse action fn is a callable method with 0-3 arguments, called as C{fn(s,loc,toks)},
             C{fn(loc,toks)}, C{fn(toks)}, or just C{fn()}, where:
              - s   = the original string being parsed (see note below)
              - loc = the location of the matching substring
              - toks = a list of the matched tokens, packaged as a C{L{ParseResults}} object
             If the functions in fns modify the tokens, they can return them as the return
             value from fn, and the modified list of tokens will replace the original.
             Otherwise, fn does not need to return any value.
  
             Note: the default parsing behavior is to expand tabs in the input string
             before starting the parsing process.  See L{I{parseString}<parseString>} for more information
             on parsing strings containing C{<TAB>}s, and suggested methods to maintain a
             consistent view of the parsed string, the parse location, and line and column
             positions within the parsed string.