def parse!(str, ber: false)
      @elements[@root].parse!(str.dup.force_encoding('BINARY'), ber: ber)
    end
def parse!(str, ber: false)
      @elements[@root].parse!(str.dup.force_encoding('BINARY'), ber: ber)
    end
Parse a DER/BER encoded string, and modify object in-place.
 @param [String] str
 @param [Boolean] ber accept BER encoding or not
 @return [Integer] number of parsed bytes
 @raise [ASN1Error] error on parsing