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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_variable(vid, variables):
 """Retrieve an input variable from our existing pool of options. """

    if isinstance(vid, six.string_types):
        vid = get_base_id(vid)
    else:
        vid = _get_string_vid(vid)
    for v in variables:
        if vid == get_base_id(v["id"]):
            return copy.deepcopy(v)
    raise ValueError("Did not find variable %s in \n%s" % (vid, pprint.pformat(variables)))