I don't think so... It prompts for execution of code that is already built up in `code_lines`... 

At the start of each iteration, it checks if we are back to no indentation. If we are, it runs whatever the last chunk of code was that we built up.

At the last iteration, if there is any code that ended without being at `indent == 0`, it executes that.

I'm doing it this way so I don't have to do a look-ahead check:

```python
for i, line in enumerate(lines):
  if lines[i+1] has indent == 0 or is final line:
    execute(code_lines)
  else:
    code_lines.append(lines[i])
```

instead I'm doing

```python
for line in lines:
  # If we're back to no indenting, then we have completed a block,
  # so run the code.
  if indent == 0:
    execute(code_lines)
    code_lines = []
  
  # Start building a new block with the current line.
  code_lines.append(line)

# If there was anything left in the current block,
# run that code also.
execute_code(lines)
```