code: func (idf identityFilter) toMemberFilter(identityInfoByID map[string]api.PeerIdentityInfo) memberFilter {
  	return func(member NetworkMember) bool {
  		identity, exists := identityInfoByID[string(member.PKIid)]
  		if !exists {
  			return false
  		}
  		return idf(identity.Identity)
  	}
  }
docs: // toMemberFilter converts this identityFilter to a memberFilter based on the given mapping
  // from PKI-ID as strings, to PeerIdentityInfo which holds the peer identities