def intersperse(sep, iterable):

    for i, item in enumerate(iterable):
        if i: yield sep
        yield item

# helper
A private observer for the `condition` attribute.
dataset/ETHPy150Open hvr/trac-git-plugin/tracext/git/git_fs.py/intersperse--crossover with--dataset/ETHPy150Open ContinuumIO/ashiba/enaml/enaml/core/conditional.py/Conditional._observe_condition