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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_integrations(integrations, with_defaults=True):
 # type: (List[Integration], bool) -> Dict[str, Integration] """Given a list of integration instances this installs them all. When `with_defaults` is set to `True` then all default integrations are added unless they were already provided before. """

    integrations = dict(
        (integration.identifier, integration) for integration in integrations or ()
    )

    logger.debug("Setting up integrations (with default = %s)", with_defaults)

    if with_defaults:
        for integration_cls in iter_default_integrations():
            if integration_cls.identifier not in integrations:
                instance = integration_cls()
                integrations[instance.identifier] = instance

    for identifier, integration in iteritems(integrations):
        with _installer_lock:
            if identifier not in _installed_integrations:
                logger.debug(
                    "Setting up previously not enabled integration %s", identifier
                )
                try:
                    type(integration).setup_once()
                except NotImplementedError:
                    if getattr(integration, "install", None) is not None:
                        logger.warn(
                            "Integration %s: The install method is "
                            "deprecated. Use `setup_once`.",
                            identifier,
                        )
                        integration.install()
                    else:
                        raise
                _installed_integrations.add(identifier)

    for identifier in integrations:
        logger.debug("Enabling integration %s", identifier)

    return integrations