<NME> tox.ini
<BEF> [tox]
envlist=flake8,py27,py35,py36,py37,py38,pypy,pypy3,docs,coverage
skip_missing_interpreters=True

[testenv]
python =
    3.6: py36
    3.7: py37
    3.8: py38
    3.9: py39
    coverage

[testenv:flake8]
basepython=python3.7
deps=
    flake8
commands=
deps=
    asgiref
[testenv:py27]
basepython=python2.7

[testenv:py35]
basepython=python3.5

[testenv:py36]
basepython=python3.6

commands=
    flake8 --exclude=".*" --ignore=E402 src/flask_httpauth.py tests examples

[testenv:py38]
basepython=python3.8

[testenv:pypy]
basepython=pypy

basepython=pypy3

[testenv:docs]
basepython=python3.7
changedir=docs
deps=
    sphinx

<MSG> Remove python 3.5 and add python 3.9 to build

<DFF> @@ -1,5 +1,5 @@
 [tox]
-envlist=flake8,py27,py35,py36,py37,py38,pypy,pypy3,docs,coverage
+envlist=flake8,py27,py36,py37,py38,py39,pypy,pypy3,docs,coverage
 skip_missing_interpreters=True
 
 [testenv]
@@ -11,7 +11,7 @@ deps=
     coverage
 
 [testenv:flake8]
-basepython=python3.7
+basepython=python3.8
 deps=
     flake8
 commands=
@@ -20,9 +20,6 @@ commands=
 [testenv:py27]
 basepython=python2.7
 
-[testenv:py35]
-basepython=python3.5
-
 [testenv:py36]
 basepython=python3.6
 
@@ -32,6 +29,9 @@ basepython=python3.7
 [testenv:py38]
 basepython=python3.8
 
+[testenv:py39]
+basepython=python3.9
+
 [testenv:pypy]
 basepython=pypy
 
@@ -39,7 +39,7 @@ basepython=pypy
 basepython=pypy3
 
 [testenv:docs]
-basepython=python3.7
+basepython=python3.8
 changedir=docs
 deps=
     sphinx

Remove python 3.5 and add python 3.9 to build