* **Machine Learning**: it normally requires lots of "matrix" and "vector" multiplications. Think of a huge spreadsheet with numbers and multiplying all of them together at the same time.

## Developing

If you already cloned the <a href="https://github.com/fastapi/fastapi" class="external-link" target="_blank">fastapi repository</a> and you want to deep dive in the code, here are some guidelines to set up your environment.

### Virtual environment

     * is the only one in use, but if we encounter nested concatenations, we start a deque of
     * meta-iterators rather than letting the nesting get arbitrarily deep.  This keeps each
     * operation O(1).
     */

    @CheckForNull private Iterator<? extends Iterator<? extends T>> topMetaIterator;

    // Only becomes nonnull if we encounter nested concatenations.

			Prefixes:    []string{"dir/day_id=2017-10-10/"},
		},
		// ListObjectsResult-37 list with prefix match 2 levels deep
		37: {
			IsTruncated: false,
			Objects: []ObjectInfo{
				{Name: "foo/201910/1112"},
				{Name: "foo/201910/1122"},
			},
		},
		// ListObjectsResult-38 list with prefix match 1 level deep
		38: {
			IsTruncated: false,
			Objects: []ObjectInfo{
				{Name: "foo/201910/1112"},

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[21:22] hl[21:22] *}

### Create a Session Dependency

A **`Session`** is what stores the **objects in memory** and keeps track of any changes needed in the data, then it **uses the `engine`** to communicate with the database.

  Set<V> createCollection() {
    return Platform.newLinkedHashSetWithExpectedSize(valueSetCapacity);
  }

  /**
   * {@inheritDoc}
   *
   * <p>Creates a decorated insertion-ordered set that also keeps track of the order in which
   * key-value pairs are added to the multimap.
   *
   * @param key key to associate with values in the collection
   * @return a new decorated set containing a collection of values for one key

   * elements.length) are all {@code null}.
   */
  @VisibleForTesting @CheckForNull transient @Nullable Object[] elements;

  /**
   * Keeps track of metadata like the number of hash table bits and modifications of this data
   * structure (to make it possible to throw ConcurrentModificationException in the iterator). Note

    /** @return {@code true} if the current thread has acquired this lock. */
    boolean isAcquiredByCurrentThread();
  }

  /**
   * A {@code LockGraphNode} associated with each lock instance keeps track of the directed edges in
   * the lock acquisition graph.
   */
  private static class LockGraphNode {

    /**
     * The map tracking the locks that are known to be acquired before this lock, each associated

Het toevoegen van type hints verandert normaal gesproken niet wat er gebeurt in je programma t.o.v. wat er zonder type hints zou gebeuren.

Maar stel je voor dat je weer bezig bent met het maken van een functie, maar deze keer met type hints.

Op hetzelfde moment probeer je de automatische aanvulling te activeren met `Ctrl+Spatie` en je ziet:

<img src="/img/python-types/image02.png">

--#{$color}: #{$value};\n  }\n\n  @each $color, $value in $theme-colors {\n    --#{$color}: #{$value};\n  }\n\n  @each $bp, $value in $grid-breakpoints {\n    --breakpoint-#{$bp}: #{$value};\n  }\n\n  // Use `inspect` for lists so that quoted items keep the quotes.\n  // See https://github.com/sass/sass/issues/2383#issuecomment-336349172\n  --font-family-sans-serif: #{inspect($font-family-sans-serif)};\n  --font-family-monospace: #{inspect($font-family-monospace)};\n}\n","// stylelint-disable dec...