*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

    style V1Field fill:#fff6f0
    style V2Field fill:#f9fff3
```

In some cases, it's even possible to have both Pydantic v1 and v2 models in the same **path operation** in your FastAPI app:

{* ../../docs_src/pydantic_v1_in_v2/tutorial003_an_py310.py hl[2:3,6,12,21:22] *}

In this example above, the input model is a Pydantic v1 model, and the output model (defined in `response_model=ItemV2`) is a Pydantic v2 model.

 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,

			wantErr: `Each form field that you specify in a form must appear in the list of policy conditions. "X-Amz-Checksum-Algorithm" not specified in the policy.`,
		},
		{
			name:    "unknown key XAmzChecksumCRC32 is error as it does not appear in policy",
			fv:      defaultFormVals.Clone().Set(http.CanonicalHeaderKey(xhttp.AmzChecksumCRC32), "crc32-val"),

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,

  /** Returns the time that this entry was last accessed, in ns. */
  @SuppressWarnings("GoodTime")
  long getAccessTime();

  /** Sets the entry access time in ns. */
  @SuppressWarnings("GoodTime") // b/122668874
  void setAccessTime(long time);

  /** Returns the next entry in the access queue. */
  ReferenceEntry<K, V> getNextInAccessQueue();

  /** Sets the next entry in the access queue. */

In this case, the HTTP header `Content-Type` will be set to `text/html`.

And it will be documented as such in OpenAPI.

///

### Return a `Response` { #return-a-response }

As seen in [Return a Response directly](response-directly.md), you can also override the response directly in your *path operation*, by returning it.

 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

/*
 * Copyright 2019 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

      assertEqualsSame(expected, in, is('-').or(is('#')).collapseFrom(in, replacement));
      assertEqualsSame(expected, in, isNot('x').collapseFrom(in, replacement));
      assertEqualsSame(expected, in, is('x').negate().collapseFrom(in, replacement));
      assertEqualsSame(expected, in, anyOf("-").collapseFrom(in, replacement));
      assertEqualsSame(expected, in, anyOf("-#").collapseFrom(in, replacement));