$ poetry update black
Updating dependencies
Resolving dependencies... (0.1s)
SolverProblemError
Because no versions of black match >20.8b1,<21.0
and black (20.8b1) depends on click (>=7.1.2), black (>=20.8b1,<21.0) requires click (>=7.1.2).
And because textx-ls-core (0.1.1) depends on click (7.0)
and no versions of textx-ls-core match >0.1.1,<0.2.0, black (>=20.8b1,<21.0) is incompatible with textx_ls_core (>=0.1.1,<0.2.0).
So, because tsdoc0 depends on both textx_ls_core (^0.1.1) and black (^20.8b1), version solving failed.