[Python] What is the best way to filter the groups that have at least N rows that meets the...

This is my DataFrame:

import pandas as pd
df = pd.DataFrame({
'a': [10, 20, 30, 50, 50, 50, 4, 100],
'b': [30, 3, 200, 25, 24, 31, 29, 2],
'd': list('aaabbbcc')
})


Expected output:

a b d
0 10 30 a
1 20 3 a
2 30 200 a


The grouping is by column d. I want to return the groups that have at least two instances of this mask

m = (df.b.gt(df.a))


This is what I have tried. It works but I wonder if there is a better/more efficient way to do it.

out = df.groupby('d').filter(lambda x: len(x.loc[x.b.gt(x.a)]) >= 2)

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