    # File lib/fog/aws/requests/compute/associate_address.rb, line 43
            def associate_address(instance_id=nil, public_ip=nil, network_interface_id=nil, allocation_id=nil)
              public_ip = allocation_id.nil? ? public_ip : nil
              response = Excon::Response.new
              response.status = 200
              instance = self.data[:instances][instance_id]
              address = public_ip.nil? ? nil : self.data[:addresses][public_ip]
              if ((instance && address) || (instance &&  !allocation_id.nil?) || (!allocation_id.nil? && !network_interface_id.nil?))
                if !allocation_id.nil?
                  allocation_ip = describe_addresses( 'allocation-id'  => "#{allocation_id}").body['addressesSet']
                  public_ip = allocation_ip['publicIp']
                end
                if current_instance = self.data[:instances][address['instanceId']]
                  current_instance['ipAddress'] = current_instance['originalIpAddress']
                end
                address['instanceId'] = instance_id
                # detach other address (if any)
                if self.data[:addresses][instance['ipAddress']]
                  self.data[:addresses][instance['ipAddress']]['instanceId'] = nil
                end
                instance['ipAddress'] = public_ip
                instance['dnsName'] = Fog::AWS::Mock.dns_name_for(public_ip)
                response.status = 200
                if !instance_id.nil? && !public_ip.nil?
                  response.body = {
                    'requestId' => Fog::AWS::Mock.request_id,
                    'return'    => true
                  }
                elsif !allocation_id.nil?
                  response.body = {
                    'requestId'     => Fog::AWS::Mock.request_id,
                    'return'        => true,
                    'associationId' => Fog::AWS::Mock.request_id
                  }
                end
                response
              #elsif ! network_interface_id.nil? && allocation_id.nil?
              #  raise Fog::Compute::AWS::NotFound.new("You must specify an AllocationId when specifying a NetworkInterfaceID")
              #elsif instance.nil? && network_interface_id.nil?
              #  raise Fog::Compute::AWS::Error.new("You must specify either an InstanceId or a NetworkInterfaceID")
              #elsif !instance && !network_interface_id
              #  raise Fog::Compute::AWS::Error.new(" 2 You must specify either an InstanceId or a NetworkInterfaceID")
              elsif !instance
                raise Fog::Compute::AWS::NotFound.new("You must specify either an InstanceId or a NetworkInterfaceID")
              elsif !address
                raise Fog::Compute::AWS::Error.new("AuthFailure => The address '#{public_ip}' does not belong to you.")
              end
            end