Problem

When I use fill_between, I typically want a plotted line as well. A nice way of doing this on several axes is to use a dict of keyword arguments, e.g.

kw = dict(color: 'red', ls='--', lw=1)ax.plot(..., **kw)ax.fill_between(..., **kw)

One thing that can't be set this way is thedrawstyle, because for some reasonfill_between has its own syntax for this which differs from other methods.

Both the argument name and the way it's processed are different:

• plot takesdrawstyle ords, with options 'default', 'steps', 'steps-pre', 'steps-mid', 'steps-post'
• fill_between takesstep with options 'pre', 'post', 'mid', and requires you to not pass in astep argument to get the default interpolating behaviour

This makes it really annoying to use, especially when automating.

Also has created some confusion in the past:#19524

Proposed solution

1. Adddrawstyle andds arguments tofill_between, that are processed the same as forplot
2. Deprecate thestep argument tofill_between