unnecessary-collection-call (C408)

Derived from the flake8-comprehensions linter.

Fix is always available.

What it does

Checks for unnecessary dict, list or tuple calls that can be rewritten as empty literals.

Why is this bad?

It's unnecessary to call e.g., dict() as opposed to using an empty literal ({}). The former is slower because the name dict must be looked up in the global scope in case it has been rebound.

Examples

dict()
dict(a=1, b=2)
list()
tuple()

Use instead:

{}
{"a": 1, "b": 2}
[]
()