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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 list_elb(region, filter_by_kwargs):
 """List all load balancers."""

    conn = boto.ec2.elb.connect_to_region(region)
    instances = conn.get_all_load_balancers()
    return lookup(instances, filter_by=filter_by_kwargs)