This
'*'
specifies an argument that can be supplied only by keyword.Quote:keyword-only: specifies an argument that can be supplied only by keyword. Keyword-only parameters can be defined by including a single var-positional parameter or bare *
in the parameter list of the function definition before them, for example kw_only1 and kw_only2 in the following:
def func(arg, *, kw_only1, kw_only2): ...