# File lib/fog/aws/requests/rds/create_db_subnet_group.rb, line 27
        def create_db_subnet_group(name, subnet_ids, description = name)
          response = Excon::Response.new
          if self.data[:subnet_groups] && self.data[:subnet_groups][name]
            raise Fog::AWS::RDS::IdentifierTaken.new("DBSubnetGroupAlreadyExists => The subnet group '#{name}' already exists")
          end

          # collection = Fog::Compute::AWS.new(:aws_access_key_id => 'mock key', :aws_secret_access_key => 'mock secret')
          compute_data = Fog::Compute::AWS::Mock.data[self.region][self.aws_access_key_id]

          subnets = subnet_ids.map do |snid|
            subnet = compute_data[:subnets].detect { |s| s['subnetId'] == snid }
            raise Fog::AWS::RDS::NotFound.new("InvalidSubnet => The subnet '#{snid}' was not found") if subnet.nil?
            subnet
          end
          vpc_id = subnets.first['vpcId']

          data = {
            'DBSubnetGroupName' => name,
            'DBSubnetGroupDescription' => description,
            'SubnetGroupStatus' => 'Complete',
            'Subnets' => subnet_ids,
            'VpcId' => vpc_id
          }
          self.data[:subnet_groups][name] = data
          response.body = {
            "ResponseMetadata"=>{ "RequestId"=> Fog::AWS::Mock.request_id },
            'CreateDBSubnetGroupResult' => { 'DBSubnetGroup' => data }
          }
          response
        end