{
          "openapi": "3.0.0",
          "info": { "title": "Workday Calculation API", "version": "v1" },
          "servers": [{ "url": "???" }],
          "paths": {
            "/workdays": {
              "get": {
                "summary": "Calculates workdays between two dates.",
                "parameters": [
                  { "name": "start", "in": "query", "required": true, "schema": { "type": "string", "format": "date-time" } },
                  { "name": "end", "in": "query", "required": true, "schema": { "type": "string", "format": "date-time" } },
                  { "name": "region", "in": "query", "required": false, "schema": { "type": "string" } },
                  { "name": "workdays", "in": "query", "required": false, "schema": { "type": "string" } }
                ],
                "responses": {
                  "200": {
                    "description": "Success",
                    "content": { "application/json": { "schema": { "type": "integer" } } }
                  }
                }
              }
            }
          }
        }