### Policy

An IAM policy in JSON format that you want to use as an inline session policy. This parameter is optional. Passing policies to this operation returns new temporary credentials. The resulting session's permissions are the intersection of the canned policy name and the policy set here. You cannot use this policy to grant more permissions than those allowed by the canned policy name being assumed.

</div>

This means that it will **always have a value**, it's just that sometimes the value could be `None` (or `null` in JSON).

That means that, clients using your API don't have to check if the value exists or not, they can **assume the field will always be there**, but just that in some cases it will have the default value of `None`.

////

/// tip

Every time you install a **new package** in that environment, **activate** the environment again.

This makes sure that if you use a **terminal (<abbr title="command line interface">CLI</abbr>) program** installed by that package, you use the one from your virtual environment and not any other that could be installed globally, probably with a different version than what you need.

///

     * method as the server should have performed that filtering already. The
     * attributes are asserted here only because server file systems may not
     * support filtering by all attributes (e.g. even though ATTR_DIRECTORY was
     * specified the server may still return objects that are not directories).
     */
    @Override

import java.io.IOException;
import java.io.OutputStream;

/**
 * An {@link OutputStream} that maintains a hash of the data written to it.
 *
 * @author Zoe Piepmeier
 * @since 16.0
 */
@Beta
public final class HashingOutputStream extends FilterOutputStream {
  private final Hasher hasher;

  /**
   * Creates an output stream that hashes using the given {@link HashFunction}, and forwards all

      assertWithMessage("quantile at index " + index)
          .that(percentiles().index(index).computeInPlace(dataset))
          .isWithin(ALLOWED_ERROR)
          .of(expectedLargeDatasetPercentile(index));
    }

    // Assert that the dataset contains the same elements after the in-place computation (although
    // they may be reordered). We only do this for one index rather than for all indexes, as it is

      assertWithMessage("quantile at index " + index)
          .that(percentiles().index(index).computeInPlace(dataset))
          .isWithin(ALLOWED_ERROR)
          .of(expectedLargeDatasetPercentile(index));
    }

    // Assert that the dataset contains the same elements after the in-place computation (although
    // they may be reordered). We only do this for one index rather than for all indexes, as it is

     *
     * We need to apply the settings and ack them atomically. This is because some HTTP/2
     * implementations (nghttp2) forbid peers from taking advantage of settings before they have
     * acknowledged! In particular, we shouldn't send frames that assume a new `initialWindowSize`
     * until we send the frame that acknowledges this new size.
     *

You can use the `jsonable_encoder` to convert the input data to data that can be stored as JSON (e.g. with a NoSQL database). For example, converting `datetime` to `str`.

{* ../../docs_src/body_updates/tutorial001_py310.py hl[28:33] *}

`PUT` is used to receive data that should replace the existing data.

### Warning about replacing { #warning-about-replacing }

That means that if you want to update the item `bar` using `PUT` with a body containing:

   *
   *   o DIRTY lines track that an entry is actively being created or updated. Every successful
   *     DIRTY action should be followed by a CLEAN or REMOVE action. DIRTY lines without a matching
   *     CLEAN or REMOVE indicate that temporary files may need to be deleted.
   *
   *   o CLEAN lines track a cache entry that has been successfully published and may be read. A