California: Petitioners claim over 400K signatures in LA District Attorney recall

Petitioners claim that they have over 400,000 signatures for the recall of Los Angeles District Attorney George Gascon. They need 566,857 by July 6. Note that the effort has been a long running affair (with the first set of petitions start last February, though any signatures from then are not counted in this number). 

How many signatures do they actual need? Good question --- and here's my look at the signature failure rate in previous recalls.