def getinputfile(self, outputfile, loadmetadata=True, client=None,requiremetadata=False):
        """Grabs one input file for the specified output filename (raises a KeyError exception if there is no such output, StopIteration if there are no input files for it). Shortcut for getinputfiles()"""
        if isinstance(outputfile, CLAMOutputFile):
            outputfilename = str(outputfile).replace(os.path.join(self.projectpath,'output/'),'')
        else:
            outputfilename = outputfile
        if outputfilename not in self:
            raise KeyError("No such outputfile " + outputfilename)
        try:
            return next(self.getinputfiles(outputfile,loadmetadata,client,requiremetadata))
        except StopIteration:
            raise StopIteration("No input files for outputfile " + outputfilename)