Global declaration is ignored by method extraction

Do method extraction on the `g = 2` line:

```python
g = None

def f():
    global g

    g = 2

f() 
print(g)
```

**Actual**

```python
g = None

def f():
    global g

    _g()

def _g():
    g = 2

f()
print(g)
```

**Expected**

```python
g = None

def f():
    global g

    _g()

def _g():
    global g
    g = 2

f()
print(g)
```