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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 _setup_default_permissions(instance):
 """Separate method to conveniently call it from scripts for example."""

    from abilian.services import get_service

    security = get_service("security")
    for permission, roles in instance.__default_permissions__:
        if permission == "create":
            # use str for comparison instead of `abilian.services.security.CREATE`
            # symbol to avoid imports that quickly become circular.
            #
            # FIXME: put roles and permissions in a separate, isolated module.
            continue
        for role in roles:
            security.add_permission(permission, role, obj=instance)