MetricsKeys without "=="

Is it possible to set the MetricsKeys for Layers without the “==”?
When I do this, it always sets the Metrics Key “==B”. Does it have to do with the Distinction between the layer.setLeftMetricsKey_() and glyph.setLeftMetricsKey_() methods?

for glyph in thisFont.glyphs:
	for layer in glyph.layers:
 		layer.setLeftMetricsKey_("B")

I am trying to rewrite the Remove Layer specific Metrics Keys script for specific needs, since it doesn’t do (anymore?) what is was supposed to do.

yes.

So the “==” will aways come up, when a metrics key is set to a layer instead of a glyph?

yes.

OK. Thanks.