code: func In(left, right OperandBuilder, other ...OperandBuilder) ConditionBuilder {
  	other = append([]OperandBuilder{left, right}, other...)
  	return ConditionBuilder{
  		operandList: other,
  		mode:        inCond,
  	}
  }
docs: // In returns a ConditionBuilder representing the result of the IN function
  // in DynamoDB Condition Expressions. The resulting ConditionBuilder can be used
  // as a part of other Condition Expressions or as an argument to the
  // WithCondition() method for the Builder struct.
  //
  // Example:
  //
  //     // condition represents the condition where the value of the item
  //     // attribute "Color" is checked against the list of colors "red",
  //     // "green", and "blue".
  //     condition := expression.In(expression.Name("Color"), expression.Value("red"), expression.Value("green"), expression.Value("blue"))
  //
  //     // Used in another Condition Expression
  //     anotherCondition := expression.Not(condition)
  //     // Used to make an Builder
  //     builder := expression.NewBuilder().WithCondition(condition)
  //
  // Expression Equivalent:
  //
  //     expression.In(expression.Name("Color"), expression.Value("red"), expression.Value("green"), expression.Value("blue"))
  //     // Let :red, :green, :blue be ExpressionAttributeValues representing the
  //     // values "red", "green", and "blue" respectively
  //     "Color IN (:red, :green, :blue)"