And be compatible with all of them at the same time.

Create a utility function to hash a password coming from the user.

And another utility to verify if a received password matches the hash stored.

And another one to authenticate and return a user.

=== "Python 3.10+"

import com.google.common.primitives.Ints;
import com.google.common.primitives.Longs;
import java.util.Comparator;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A utility for performing a chained comparison statement. <b>Note:</b> Java 8+ users should
 * generally prefer the methods in {@link Comparator}; see <a href="#java8">below</a>.
 *
 * <p>Example usage of {@code ComparisonChain}:
 *

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Assists in resolving the dependencies of a plugin. <strong>Warning:</strong> This is an internal utility class that
 * is only public for technical reasons, it is not part of the public API. In particular, this class can be changed or
 * deleted without prior notice.
 *
 * @since 3.0
 */
@Named
@Singleton

import org.eclipse.aether.util.filter.ExclusionsDependencyFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Assists the project builder. <strong>Warning:</strong> This is an internal utility class that is only public for
 * technical reasons, it is not part of the public API. In particular, this class can be changed or deleted without
 * prior notice.
 *
 */
@Named
@Singleton

// starting offset is aligned up to the nearest block edge, and each
// ending offset is aligned down to the nearest block edge.
//
// Even though the Go tar Reader and the BSD tar utility can handle entries
// with arbitrary offsets and lengths, the GNU tar utility can only handle
// offsets and lengths that are multiples of blockSize.
func alignSparseEntries(src []sparseEntry, size int64) []sparseEntry {
	dst := src[:0]
	for _, s := range src {

### Other utility functions

Any other utility function that you call directly can be created with normal `def` or `async def` and FastAPI won't affect the way you call it.

This is in contrast to the functions that FastAPI calls for you: *path operation functions* and dependencies.

import org.eclipse.aether.repository.LocalRepository;
import org.eclipse.aether.repository.LocalRepositoryManager;
import org.eclipse.aether.repository.RemoteRepository;

/**
 * <strong>Warning:</strong> This is an internal utility class that is only public for technical reasons, it is not part
 * of the public API. In particular, this class can be changed or deleted without prior notice.
 *
 */
@Deprecated

      </replaceConfiguration>

import org.eclipse.aether.artifact.Artifact;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Manages the class realms used by Maven. <strong>Warning:</strong> This is an internal utility class that is only
 * public for technical reasons, it is not part of the public API. In particular, this class can be changed or deleted
 * without prior notice.
 *
 */
@Named
@Singleton

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.HashMap;
import java.util.Map;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Static utility methods pertaining to {@link Escaper} instances.
 *
 * @author Sven Mawson
 * @author David Beaumont
 * @since 15.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class Escapers {