I use this very strict config with mypy and it's effectively a typed language. I rarely have any errors in runtime now, at least from type-related problems like assigning 'vals = 3' and later trying to call 'vals.append(4)'. I sometimes use 'Any' because it's basically required for things like loading JSON or retrieving the results from a GET request, but I have several strictness settings that ensure I never pass around wild Any values and I try to keep their use to within a single function or method and always return a well-typed value. Sure it's all in my IDE right now, but if I import 1 or 2 packages suddenly my well-typed Python code starts to act more like a typed language in runtime, too!

    disallow_any_unimported = true
    disallow_any_expr = true
    disallow_any_decorated = false # true if you never plan to use Any
    disallow_any_explicit = false # true if you never plan to use Any
    disallow_any_generics = false # true if you never plan to use Any
    disallow_subclassing_any = true
    disallow_untyped_calls = true
    disallow_untyped_defs = true
    disallow_incomplete_defs = true
    disallow_untyped_decorators = true
    no_implicit_optional = true
    warn_redundant_casts = true
    warn_unused_ignores = true
    no_warn_no_return = true
    warn_return_any = true
    warn_unreachable = true
    strict_equality = true
    strict = true