autoflake should ignore unused variables starting with '_'

[yoursvivek]

autoflake --remove-unused-variables option should not remove variable with names starting with underscore. Or at least they it should give an opt-in feature.

For test file t.py as follows

def fetch_user(value):
    "let's say it returns user or raises Exception when user isn't found"
    return {"pk": 2}

def fetch_settings(value):
    "let's say it returns user settings or raises Exception when settings isn't found"
    return {"pk": 3}

def check_user_regn_complete(value):
    user = fetch_user(value)
    _settings = fetch_settings(value)

Result of running autoflake --remove-unused-variables t.py

--- original/t.py
+++ fixed/t.py
@@ -7,5 +7,5 @@
     return {"pk": 3}
 
 def check_user_regn_complete(value):
-    user = fetch_user(value)
-    _settings = fetch_settings(value)
+    fetch_user(value)
+    fetch_settings(value)

Assignment to variable _settings is a good practice as opposed to not assigning it at all.

Expected result:

--- original/t.py
+++ fixed/t.py
@@ -7,6 +7,6 @@
     return {"pk": 3}
 
 def check_user_regn_complete(value):
-    user = fetch_user(value)
+    fetch_user(value)
     _settings = fetch_settings(value)