assertThat(arr).hasLength(i);
        for (int j = 0; j < i; j++) {
          assertThat(arr[j]).isEqualTo(VALUES[j]);
        }
      }
    }
  }

  @SuppressWarnings("nullness") // test of a bogus call
  public void testToArray_withNull() {
    List<@Nullable Boolean> list = Arrays.asList(false, true, null);
    assertThrows(NullPointerException.class, () -> Booleans.toArray(list));
  }

这是一个非常简单的程序。

但现在想象你要从零开始写它。

在某个时刻你开始定义函数，并且准备好了参数……

接下来你需要调用“那个把首字母变大写的方法”。

是 `upper`？是 `uppercase`？`first_uppercase`？还是 `capitalize`？

然后，你试试程序员的老朋友——编辑器的自动补全。

你输入函数的第一个参数 `first_name`，再输入一个点（`.`），然后按下 `Ctrl+Space` 触发补全。

但很遗憾，没有什么有用的提示：

<img src="/img/python-types/image01.png">

### 添加类型 { #add-types }

我们来改前一个版本的一行代码。

把函数参数从：

```Python
    first_name, last_name
```

改成：

		return
	}

	if err := par.IsValid(); err != nil {
		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrAdminConfigBadJSON), r.URL)
		return
	}

	// Call IAM subsystem
	updatedAt, addedOrRemoved, _, err := globalIAMSys.PolicyDBUpdateLDAP(ctx, isAttach, par)
	if err != nil {
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
		return
	}

if NOT "%FESS_HEAP_SIZE%" == "" set FESS_MIN_MEM=%FESS_HEAP_SIZE%
if NOT "%FESS_HEAP_SIZE%" == "" set FESS_MAX_MEM=%FESS_HEAP_SIZE%

call:convertxm %FESS_MIN_MEM% JVM_XMS
call:convertxm %FESS_MAX_MEM% JVM_XMX

CALL "%FESS_HOME%\bin\fess.in.bat"

rem thread stack size
set JVM_SS=256

    return backingMap.get(element);
  }

  // Optional Operations - Modification Operations

  /**
   * {@inheritDoc}
   *
   * @throws IllegalArgumentException if the call would result in more than {@link
   *     Integer#MAX_VALUE} occurrences of {@code element} in this multiset.
   */
  @CanIgnoreReturnValue
  @Override
  public final int add(@ParametricNullness E element, int occurrences) {

        SmbFile parent = newParent();
        List<FileEntry> entries = Arrays.asList(entry("bad", SmbConstants.TYPE_SHARE), entry("good", SmbConstants.TYPE_SHARE));

        // First call throws, second accepts
        when(filter.accept(any())).thenThrow(new CIFSException("boom")).thenReturn(true);

        ShareEnumIterator it = new ShareEnumIterator(parent, entries.iterator(), filter);

        What is the problem, question, or error?

        Write a short description telling me what you are doing, what you expect to happen, and what is currently happening.
      placeholder: |
        * Open the browser and call the endpoint `/`.
        * It returns a JSON with `{"Hello": "World"}`.
        * But I expected it to return `{"Hello": "Sara"}`.
    validations:
      required: true
  - type: dropdown
    id: os
    attributes:

		return false
	}
	m.RecvSeq++
	return true
}

// response will send handleIncoming response to client.
// may never block.
// Should return whether the next call would block.
func (m *muxClient) response(seq uint32, r Response) {
	if debugReqs {
		fmt.Println(m.MuxID, m.parent.String(), "RESP")
	}
	if debugPrint {

<div class="termy">

```console
$ python -m venv .venv
```

</div>

/// details | What that command means

* `python`: use the program called `python`
* `-m`: call a module as a script, we'll tell it which module next
* `venv`: use the module called `venv` that normally comes installed with Python
* `.venv`: create the virtual environment in the new directory `.venv`

///

////

the function call.
</p>

<p>
The final case, a value-receiver function for a pointer-receiver method,
is illegal because pointer-receiver methods are not in the method set
of the value type.
</p>

<p>
Function values derived from methods are called with function call syntax;
the receiver is provided as the first argument to the call.