def add_child_hash(self, child_hash):
<EOL>if not (isinstance(child_hash,PCABinaryProjections) or isinstance(child_hash,RandomBinaryProjections) or isinstance(child_hash,RandomBinaryProjectionTree)):<EOL><INDENT>raise ValueError('<STR_LIT>')<EOL><DEDENT>self.child_hashes.append(child_hash)<EOL>
Adds specified child hash.

The hash must be one of the binary types.