272 

   273 def _isnamedfunc(x, funcname):

   274     """Check if given tree matches named function"""

   275     return x and x[0] == 'func' and getsymbol(x[1]) == funcname

   276 

   277 def _isposargs(x, n):

   278     """Check if given tree is n-length list of positional arguments"""

   279     l = getlist(x)

   280     return len(l) == n and all(y and y[0] != 'keyvalue' for y in l)

   281 

   282 def _matchnamedfunc(x, funcname):

   283     """Return args tree if given tree matches named function; otherwise None

   284 

   285     This can't be used for testing a nullary function since its args tree

   286     is also None. Use _isnamedfunc() instead.

   287     """

   288     if not _isnamedfunc(x, funcname):

   289         return

   290     return x[2]