Move refactor function between modules fails when there is a decorator

[lieryan]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Code before refactoring:

# mod1.py
def hello(func):
    return func
@hello
def foo():
    pass

# mod2.py
print("test")

2. Move refactor mod1.foo() to mod2

3. Expected code after refactoring:

# mod1.py
def hello(func):
    return func

# mod2.py
from func import hello

@hello
def foo():
    pass

print("test")

4. Describe the error or unexpected result that you are getting

Syntax error in file <mod1.py> line <4>: invalid syntax

Editor information (please complete the following information):

• Rope Python version: Python 3.8
• Rope version: 0.20.1