# File lib/mongo/lint.rb, line 62
    def validate_read_concern_option(read_concern)
      return unless enabled?
      return if read_concern.nil?
      unless read_concern.is_a?(Hash)
        raise Error::LintError, "Read concern is not a hash: #{read_concern}"
      end
      return if read_concern.empty?
      keys = read_concern.keys
      if keys != [:level]
        raise Error::LintError, "Read concern has invalid keys: #{keys.inspect}"
      end
      level = read_concern[:level]
      return if [:local, :majority, :snapshot].include?(level)
      raise Error::LintError, "Read concern level is invalid: #{level.inspect}"
    end