/** Verify all writes flag */
    int FLAGS_VERIFY_ALL_WRITES = 0x0010;
    /** Tree copy flag */
    int FLAGS_TREE_COPY = 0x0020;

    // open function
    /** Open function fail if exists */
    int OPEN_FUNCTION_FAIL_IF_EXISTS = 0x0000;
    /** Open function overwrite if exists */
    int OPEN_FUNCTION_OVERWRITE_IF_EXISTS = 0x0020;

    /** Process ID */
    int PID = (int) (Math.random() * 65536d);

// current row and stores the result.
//
// On success, it returns (nil, nil).
func (e *FuncExpr) evalAggregationNode(r Record, tableAlias string) error {
	// It is assumed that this function is called only when
	// `e` is an aggregation function.

	var val *Value
	var err error
	funcName := e.getFunctionName()
	if aggFnCount == funcName {
		if e.Count.StarArg {
			// Handle COUNT(*)
			e.aggregate.runningCount++

* the path operation decorator
* the path operation function

* the body
* the request body
* the response body
* the JSON body
* the form body
* the file body
* the function body

* the parameter
* the body parameter
* the path parameter
* the query parameter
* the cookie parameter
* the header parameter
* the form parameter
* the function parameter

* the event
* the startup event

# Dependencies - `Depends()` and `Security()`

## `Depends()`

Dependencies are handled mainly with the special function `Depends()` that takes a callable.

Here is the reference for it and its parameters.

You can import it directly from `fastapi`:

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

import java.util.Comparator;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.Set;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.function.ToIntFunction;
import java.util.stream.Collector;
import org.jspecify.annotations.Nullable;

/**

{* ../../docs_src/authentication_error_status_code/tutorial001_an_py39.py hl[9:13] *}

/// tip

Notice that the function returns the exception instance, it doesn't raise it. The raising is done in the rest of the internal code.

   *
   * @throws NullPointerException if the function returns {@code null}
   * @since 12.0
   */
  public abstract <V> Optional<V> transform(Function<? super T, V> function);

  /**
   * Returns {@code true} if {@code object} is an {@code Optional} instance, and either the
   * contained references are {@linkplain Object#equals equal} to each other or both are absent.

import java.io.Serializable;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.function.Function;
import java.util.function.ToIntFunction;
import java.util.stream.Collector;
import org.jspecify.annotations.Nullable;

/**
 * A {@link Multiset} whose contents will never change, with many other important properties

  }

  // enum singleton pattern
  private enum TrimStringFunction implements Function<String, String> {
    INSTANCE;

    @Override
    public String apply(String string) {
      return whitespace().trimFrom(string);
    }
  }

  public void testCompose() {
    Function<String, String> trim = TrimStringFunction.INSTANCE;
    Predicate<String> equalsFoo = Predicates.equalTo("Foo");

8. Notice that this *path operation function* uses regular `def` instead of `async def`.

    As always, in FastAPI you can combine `def` and `async def` as needed.

    If you need a refresher about when to use which, check out the section _"In a hurry?"_ in the docs about [`async` and `await`](../async.md#in-a-hurry){.internal-link target=_blank}.