def open_w(self, file):
        if not self.steps:
            return open(file, 'w')
        if self.steps[0][1] >= SOURCE:
            raise ValueError, \
                  'Template.open_w: pipeline begins with SOURCE'
        cmd = self.makepipeline('', file)
        return os.popen(cmd, 'w')
dataset/ETHPy150Open azoft-dev-team/imagrium/env/Lib/pipes.py/Template.open_w/operator `==` -> `>=`