/**
   * Computes the function of current and new value. Subclasses should open-code this update
   * function for most uses, but the virtualized form is needed within retryUpdate.
   *
   * @param currentValue the current value (of either base or a cell)
   * @param newValue the argument from a user update call
   * @return result of the update function
   */
  abstract long fn(long currentValue, long newValue);

  /**

# sudo apt-get update && apt-get whichever

# hadolint ignore=DL3005,DL3008
RUN apt-get update && \
  apt-get install --no-install-recommends -y \
  ca-certificates \
  curl \
  iptables \
  iproute2 \
  iputils-ping \
  knot-dnsutils \
  netcat-openbsd \
  tcpdump \
  conntrack \
  bsdmainutils \
  net-tools \
  lsof \
  sudo \
  && update-ca-certificates \
  && apt-get upgrade -y \

然后再用它生成一个只含已设置（在请求中所发送）数据，且省略了默认值的 `dict`：

```Python hl_lines="34"
{!../../docs_src/body_updates/tutorial002.py!}
```

### 使用 Pydantic 的 `update` 参数

接下来，用 `.copy()` 为已有模型创建调用 `update` 参数的副本，该参数为包含更新数据的 `dict`。

例如，`stored_item_model.copy(update=update_data)`：

```Python hl_lines="35"
{!../../docs_src/body_updates/tutorial002.py!}
```

### 更新部分数据小结

简而言之，更新部分数据应：

		t.Errorf("failed to update with named arg")
	}

	AssertEqual(t, result4, namedUser)

	if err := DB.Exec("UPDATE named_users SET name1 = @name, name2 = @name2, name3 = @name", sql.Named("name", "jinzhu-new"), sql.Named("name2", "jinzhu-new2")).Error; err != nil {
		t.Errorf("failed to update with named arg")
	}

	namedUser.Name1 = "jinzhu-new"
	namedUser.Name2 = "jinzhu-new2"

		t.Fatalf("failed to query data, got error %v", err)
	}

	AssertEqual(t, result, data)

	if err := DB.Model(&result).Update("roles", "").Error; err != nil {
		t.Fatalf("failed to update data's roles, got error %v", err)
	}

	if err := DB.First(&result, data.ID).Error; err != nil {
		t.Fatalf("failed to query data, got error %v", err)
	}
}

Next, for an individual proxy we will check if it could possibly be impacted by the change. For example, we know a sidecar never is impacted by a `Gateway` update, and we can also look at scoping (from `Sidecar.egress.hosts`) to further restrict update scopes.

            MD4 md4 = new MD4();
            md4.update(password.getBytes(SmbConstants.UNI_ENCODING));
            HMACT64 hmac = new HMACT64(md4.digest());
            hmac.update(user.toUpperCase().getBytes(SmbConstants.UNI_ENCODING));
            hmac.update(domain.toUpperCase().getBytes(SmbConstants.UNI_ENCODING));
            hmac = new HMACT64(hmac.digest());
            hmac.update(challenge);
            hmac.update(clientChallenge);

        byte[] response = new byte[24];
        MessageDigest hmac = Crypto.getHMACT64(passwordHash);
        hmac.update(Strings.getUNIBytes(user.toUpperCase()));
        hmac.update(Strings.getUNIBytes(domain.toUpperCase()));
        hmac = Crypto.getHMACT64(hmac.digest());
        hmac.update(challenge);
        hmac.update(clientChallenge);
        hmac.digest(response, 0, 16);
        System.arraycopy(clientChallenge, 0, response, 16, 8);

    }

    /*
     * (non-Javadoc)
     *
     * @see org.codelibs.fess.crawler.service.DataService#update(java.util.List)
     */
    @Override
    public void update(final List<AccessResultImpl<Long>> accessResultList) {
        for (final AccessResultImpl<Long> accessResult : accessResultList) {
            update(accessResult);
        }
    }

 *  **Request cancellation fixes.** This update fixes a bug where synchronous
    requests couldn't be canceled by tag. This update avoids crashing when
    `onResponse()` throws an `IOException`. That failure will now be logged
    instead of notifying the thread's uncaught exception handler. We've added a
    new API, `Call.isCanceled()` to check if a call has been canceled.

 *  New: Update `MultipartBuilder` to support content length.