pandas how to finds missing matching column values when merging two dataframes

Question

When matching two dfs (say A and B) on values of a column called id_number, I am trying to identify rows in A, which cannot find a matching id number in B, e.g. A is like,

id_number    name
1            a
2            b
3            c

B is like,

id_number    year
1            2007
2            2010
4            2008

I want to create a boolean column called has_b in A, result in,

id_number    name    has_b
1            a       True
2            b       True
3            c       False

I am wondering how to achieve the above dataframe.