Poetry cannot resolve dependencies (py2neo, ward)

gistfile1.txt

MBP-A36511NH:poetry-demo nlh$ poetry add ward py2neo
Using version ^0.46.0-beta.0 for ward
Using version ^4.3.0 for py2neo

Updating dependencies
Resolving dependencies... (1.9s)

[SolverProblemError]
Because no versions of py2neo match >4.3.0,<5.0.0
 and py2neo (4.3.0) depends on pygments (>=2.3.1,<2.4.0), py2neo (>=4.3.0,<5.0.0) requires pygments (>=2.3.1,<2.4.0).
And because ward (0.46.0b0) depends on pygments (>=2.4.2,<3.0.0)
 and no versions of ward match >0.46.0-beta.0,<0.47.0, py2neo (>=4.3.0,<5.0.0) is incompatible with ward (>=0.46.0-beta.0,<0.47.0).
So, because poetry-demo depends on both ward (^0.46.0-beta.0) and py2neo (^4.3.0), version solving failed.