if (requestSendStarted && requestIsOneShot(e, userRequest)) return false

    // This exception is fatal.
    if (!isRecoverable(e, requestSendStarted)) return false

    // No more routes to attempt.
    if (!call.retryAfterFailure()) return false

    // For failure recovery, use the same route selector with a new connection.
    return true
  }

  private fun requestIsOneShot(

# Path Parameters and Numeric Validations

In the same way that you can declare more validations and metadata for query parameters with `Query`, you can declare the same type of validations and metadata for path parameters with `Path`.

## Import Path

First, import `Path` from `fastapi`, and import `Annotated`:

//// tab | Python 3.10+

```Python hl_lines="1  3"
{!> ../../docs_src/path_params_numeric_validations/tutorial001_an_py310.py!}
```

import java.util.concurrent.TimeoutException;
import junit.framework.AssertionFailedError;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A helper for concurrency testing. One or more {@code TestThread} instances are instantiated in a
 * test with reference to the same "lock-like object", and then their interactions with that object
 * are choreographed via the various methods on this class.
 *

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"bufio"
	"bytes"
	"compress/gzip"
	"context"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io"
	"math/rand"
	"os"
	"reflect"
	"sort"
	"testing"
	"time"

----------------

If you experience or witness unacceptable behavior — or have any other concerns — please report it by
emailing [******@****.***][codeofconduct_at]. For more details, please see our Reporting
Guidelines below.

Thanks
------

Some of the ideas and wording for the statements and guidelines above were based on work by the
[Twitter][twitter_coc], [Ubuntu][ubuntu_coc], [GDC][gdc_coc], and [Django][django_coc] communities.

query.additional.highlighted.fields=
query.additional.search.fields=
query.additional.facet.fields=
query.additional.sort.fields=
query.additional.analyzed.fields=
query.additional.not.analyzed.fields=
query.gsa.response.fields=UE,U,T,RK,S,LANG
query.gsa.default.lang=en
query.gsa.default.sort=
query.gsa.meta.prefix=MT_
query.gsa.index.field.charset=charset
query.gsa.index.field.content_type.=content_type

 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *

Another big feature needed by APIs is data validation, making sure that the data is valid, given certain parameters. For example, that some field is an `int`, and not some random string. This is especially useful for incoming data.

Without a data validation system, you would have to do all the checks by hand, in code.