# Additional Responses in OpenAPI

/// warning

This is a rather advanced topic.

If you are starting with **FastAPI**, you might not need this.

///

You can declare additional responses, with additional status codes, media types, descriptions, etc.

Those additional responses will be included in the OpenAPI schema, so they will also appear in the API docs.

    private final File file;
    private final ImmutableSet<FileWriteMode> modes;

    private FileByteSink(File file, FileWriteMode... modes) {
      this.file = checkNotNull(file);
      this.modes = ImmutableSet.copyOf(modes);
    }

    @Override
    public FileOutputStream openStream() throws IOException {
      return new FileOutputStream(file, modes.contains(APPEND));
    }

    @Override

// sysexits to signify some error running istioctl, and use 79-125 as custom
// error codes for other info that we'd like to use to pass info on.
const (
	ExitUnknownError   = 1 // for compatibility with existing exit code
	ExitIncorrectUsage = 64
	ExitDataError      = 65 // some format error with input data

	// below here are non-zero exit codes that don't indicate an error with istioctl itself

    public static final int ERR_SSN_SRVC = 0x02;

    // name service error codes
    public static final int FMT_ERR = 0x1;
    public static final int SRV_ERR = 0x2;
    public static final int IMP_ERR = 0x4;
    public static final int RFS_ERR = 0x5;
    public static final int ACT_ERR = 0x6;
    public static final int CFT_ERR = 0x7;

    // session service error codes
    public static final int CONNECTION_REFUSED    = -1; 

 *     this.codes = ImmutableSet.copyOf(codes);
 *     checkArgument(Collections.disjoint(this.codes, RESERVED_CODES));
 *   }
 * }
 * }</pre>
 *
 * <h3>See also</h3>
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @since 2.0
 */
@DoNotMock("Use ImmutableList.of or another implementation")

Using the below example document:
<img width="85%" src="https://bradley.codes/static/img/jstream-levels.gif" alt="jstream"/>

we can choose to extract and act only the objects within the top-level array:
```go
f, _ := os.Open("input.json")

{* ../../docs_src/response_status_code/tutorial001.py hl[6] *}

`201` ist der Statuscode für „Created“ („Erzeugt“).

Aber Sie müssen sich nicht daran erinnern, welcher dieser Codes was bedeutet.

Sie können die Hilfsvariablen von `fastapi.status` verwenden.

{* ../../docs_src/response_status_code/tutorial002.py hl[1,6] *}

      for (RoundingMode mode : ALL_ROUNDING_MODES) {
        assertThrows(IllegalArgumentException.class, () -> IntMath.log2(x, mode));
      }
    }
  }

  // Relies on the correctness of BigIntegerMath.log2 for all modes except UNNECESSARY.
  public void testLog2MatchesBigInteger() {
    for (int x : POSITIVE_INTEGER_CANDIDATES) {
      for (RoundingMode mode : ALL_SAFE_ROUNDING_MODES) {

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.SampleElements.Colliders;
import java.util.List;

/**
 * A generator using sample elements whose hash codes all collide badly.
 *
 * @author Kevin Bourrillion
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestCollidingSetGenerator implements TestSetGenerator<Object> {
  @Override

    RoundToDoubleTester(BigDecimal input) {
      this.input = input;
    }

    RoundToDoubleTester setExpectation(double expectedValue, RoundingMode... modes) {
      for (RoundingMode mode : modes) {
        Double previous = expectedValues.put(mode, expectedValue);
        if (previous != null) {
          throw new AssertionError();
        }
      }
      return this;
    }