Please follow the general troubleshooting steps first:

• Ran brew update and retried your prior step?
• Ran brew doctor, fixed as many issues as possible and retried your prior step?
• If you're seeing permission errors tried running sudo chown -R $(whoami) $(brew --prefix)?
• When trying to run the System-installed Swift directly on the terminal, this error shows up:
• I am creating this issue because I've seen this same error cited as related to the Homebrew Python version on other forums.

$ swift
Traceback (most recent call last):
File "", line 1, in
File "/Applications/Xcode.app/Contents/SharedFrameworks/LLDB.framework/Resources/Python/lldb/init.py", line 98, in
import six
ImportError: No module named six
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined
Traceback (most recent call last):
File "", line 1, in
NameError: name 'run_one_line' is not defined