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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 ceph_is_installed(module):
 """ A helper callback to be executed after the connection is made to ensure that Ceph is installed. """

    ceph_package = Ceph(module.conn)
    if not ceph_package.installed:
        host = module.conn.hostname
        raise RuntimeError(
            'ceph needs to be installed in remote host: %s' % host
        )