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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_brain(brain_or_object):
 """Return a ZCatalog brain for the object :param brain_or_object: A single catalog brain or content object :type brain_or_object: ATContentType/DexterityContentType/CatalogBrain :returns: True if the object is a catalog brain :rtype: bool """

    if is_brain(brain_or_object):
        return brain_or_object
    if is_root(brain_or_object):
        return brain_or_object

    # fetch the brain by UID
    uid = get_uid(brain_or_object)
    uc = get_tool("uid_catalog")
    results = uc({"UID": uid}) or search(query={'UID': uid})
    if len(results) == 0:
        return None
    if len(results) > 1:
        fail(500, "More than one object with UID={} found in portal_catalog".format(uid))
    return results[0]