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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_nexusport_binding(port_id, vlan_id, switch_ip, instance_id):
 """Lists a nexusport binding."""

    LOG.debug("get_nexusport_binding() called")
    return _lookup_all_nexus_bindings(port_id=port_id,
                                      vlan_id=vlan_id,
                                      switch_ip=switch_ip,
                                      instance_id=instance_id)