# File lib/fog/aws/requests/compute/revoke_security_group_ingress.rb, line 61
        def revoke_security_group_ingress(group_name, options = {})
          options = Fog::AWS.parse_security_group_options(group_name, options)
          if options.key?('GroupName')
            group_name = options['GroupName']
          else
            group_name = self.data[:security_groups].reject { |k,v| v['groupId'] != options['GroupId'] } .keys.first
          end

          response = Excon::Response.new
          group = self.data[:security_groups][group_name]

          if group
            verify_permission_options(options, group['vpcId'] != nil)

            normalized_permissions = normalize_permissions(options)

            normalized_permissions.each do |permission|
              if matching_permission = find_matching_permission(group, permission)
                matching_permission['ipRanges'] -= permission['ipRanges']
                matching_permission['groups'] -= permission['groups']

                if matching_permission['ipRanges'].empty? && matching_permission['groups'].empty?
                  group['ipPermissions'].delete(matching_permission)
                end
              end
            end

            response.status = 200
            response.body = {
              'requestId' => Fog::AWS::Mock.request_id,
              'return'    => true
            }
            response
          else
            raise Fog::Compute::AWS::NotFound.new("The security group '#{group_name}' does not exist")
          end
        end