import org.jspecify.annotations.Nullable;

/**
 * A readable source of characters, such as a text file. Unlike a {@link Reader}, a {@code
 * CharSource} is not an open, stateful stream of characters that can be read and closed. Instead,
 * it is an immutable <i>supplier</i> of {@code Reader} instances.
 *
 * <p>{@code CharSource} provides two kinds of methods:
 *
 * <ul>

    protected int maxThreadCheckCount = 20;

    /** The maximum depth for crawling. A value of -1 indicates no depth check. */
    protected int maxDepth = -1;

    /** The maximum number of URLs to access. A value of 0 indicates no limit. */
    protected long maxAccessCount = 0;

    /**
     * Returns the session ID.
     * @return The session ID.
     */

  private EmptyImmutableListMultimap() {
    super(ImmutableMap.<Object, ImmutableList<Object>>of(), 0);
  }

  /*
   * TODO(b/242884182): Figure out why this helps produce the same class file when we compile most
   * of common.collect a second time with the results of the first compilation on the classpath. Or
   * just back this out once we stop doing that (which we'll do after our internal GWT setup

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful

 * primitives. The strategies are all implemented as subtypes of AtomicHelper and the strategy is
 * selected in the static initializer of AbstractFuture. This is convenient and performant but
 * introduces some testing difficulties. This test exercises the fallback strategies.
 *
 * <p>To force selection of our fallback strategies, we load {@link AbstractFuture} (and all of

      // Each element of `oldTable` is the head of a (possibly empty) linked list of elements in
      // `entries`. The `oldNext` loop is going to traverse that linked list.
      // We need to rewrite the `next` link of each of the elements so that it is in the appropriate
      // linked list starting from `newTable`. In general, each element from the old linked list

             * for whatever reason. I copy over the uid here so it appears correct
             * in logging output. Logging of andx segments of messages inadvertantly
             * print header information because of the way toString always makes a
             * super.toString() call(see toString() at the end of all smbs classes).
             */

            andx.uid = uid;

 *       with the same key. Some behaviors of {@link Multimap} are left unspecified and are provided
 *       only by the subtypes mentioned below.
 *   <dt>{@link ListMultimap}
 *   <dd>An extension of {@link Multimap} which permits duplicate entries, supports random access of
 *       values for a particular key, and has <i>partially order-dependent equality</i> as defined

 *       with the same key. Some behaviors of {@link Multimap} are left unspecified and are provided
 *       only by the subtypes mentioned below.
 *   <dt>{@link ListMultimap}
 *   <dd>An extension of {@link Multimap} which permits duplicate entries, supports random access of
 *       values for a particular key, and has <i>partially order-dependent equality</i> as defined

{* ../../docs_src/query_params_str_validations/tutorial001_py310.py hl[7] *}

The query parameter `q` is of type `str | None`, that means that it's of type `str` but could also be `None`, and indeed, the default value is `None`, so FastAPI will know it's not required.

/// note

FastAPI will know that the value of `q` is not required because of the default value `= None`.