def prefilter(self, IP, line, continuation):
"""prefilter pre-processes input to do PyRAF substitutions before
passing it on to IPython.
NOTE: this is ONLY used for VERY_OLD_IPY, since we use the transform
hooks for the later versions.
"""
line = self.cmd(str(line)) # use type str here, not unicode
return TerminalInteractiveShell._prefilter(IP, line, continuation)
