too-many-newlines-at-end-of-file (W391)

Derived from the pycodestyle linter.

Fix is always available.

This rule is unstable and in preview. The --preview flag is required for use.

What it does

Checks for files with multiple trailing blank lines.

In the case of notebooks, this check is applied to each cell separately.

Why is this bad?

Trailing blank lines in a file are superfluous.

However, the last line of the file should end with a newline.

Example

spam(1)\n\n\n

Use instead:

spam(1)\n