# Query Parameter Models { #query-parameter-models }

If you have a group of **query parameters** that are related, you can create a **Pydantic model** to declare them.

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

            .map { (_, v) -> listOf(v.maxOrNull()!!.format()) }.flatten()
    }

    private
    fun VersionNumber.format() =
        // reformat according to our versioning scheme, since toString() would typically convert 1.0 to 1.0.0
        // starting with Gradle 9.0, the version number is always 3 digits (SemVer)

            current = classesContainingMethod.get(i)
            if (!isInternal(current)) {
                // there's another public super class which contains target method
                // it would be reported somewhere else
                return false
            }
        }

        // I'm the top public class which contains target method
        return true
    }

the problem. If possible, please share a link to Colab/Jupyter/any notebook.

Also, please include a link to a GraphDef or the model if possible.

**Any other info / logs**

Include any logs or source code that would be helpful to diagnose the problem.
If including tracebacks, please include the full traceback. Large logs and files

    url: https://github.com/fastapi/fastapi/discussions/categories/questions
  - name: Feature Request
    about: To suggest an idea or ask about a feature, please start with a question saying what you would like to achieve. There might be a way to do it already.
    url: https://github.com/fastapi/fastapi/discussions/categories/questions
  - name: Show and tell
    about: Show what you built with FastAPI or to be used with FastAPI.

						all = append(all, recDst)
					}
				}()
				if err != nil {
					in.err = err
				}
				// We don't need the input any more.
				//nolint:staticcheck // SA6002 Using pointer would allocate more since we would have to copy slice header before taking a pointer.
				r.bufferPool.Put(in.input)
				in.input = nil
				in.dst <- all
			}
		}()
	}
	return nil
}

	// If nilCount >= p.writeQuorum, we return nil. This is because HealFile() uses
	// CreateFile with p.writeQuorum=1 to accommodate healing of single disk.
	// i.e if we do no return here in such a case, reduceWriteQuorumErrs() would
	// return a quorum error to HealFile().
	nilCount := countErrs(p.errs, nil)
	if nilCount >= p.writeQuorum {
		return nil
	}

	writeErr := reduceWriteQuorumErrs(ctx, p.errs, objectOpIgnoredErrs, p.writeQuorum)

case bool, string:
	printString("type is bool or string")  // type of i is type of x (interface{})
default:
	printString("don't know the type")     // type of i is type of x (interface{})
}
</pre>

<p>
could be rewritten:
</p>

<pre>
v := x  // x is evaluated exactly once
if v == nil {
	i := v                                 // type of i is type of x (interface{})
	printString("x is nil")

		return
	}

	listObjectVersions := objectAPI.ListObjectVersions

	// Initiate a list object versions operation based on the input params.
	// On success would return back ListObjectsInfo object to be
	// marshaled into S3 compatible XML header.
	listObjectVersionsInfo, err := listObjectVersions(ctx, bucket, prefix, marker, versionIDMarker, delimiter, maxkeys)
	if err != nil {

	Checksum *hash.Checksum
	MD5Hex   string
}

// fanOutPutObject takes an input source reader and fans out multiple PUT operations
// based on the incoming fan-out request, a context cancellation by the caller
// would ensure all fan-out operations are canceled.
func fanOutPutObject(ctx context.Context, bucket string, objectAPI ObjectLayer, fanOutEntries []minio.PutObjectFanOutEntry, fanOutBuf []byte, opts fanOutOptions) ([]ObjectInfo, []error) {