You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: _aggregate_operation.rs
    path of file: ./repos/aws-sdk-rust/sdk/glue/src/types
    
    the code of the file until where you have to start completion: // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.

/// <p>Specifies the set of parameters needed to perform aggregation in the aggregate transform.</p>
#[non_exhaustive]
#[derive(::std::clone::Clone, ::std::cmp::PartialEq, ::std::fmt::Debug)]
pub struct AggregateOperation {
    /// <p>Specifies the column on the data set on which
    
    pub fn build(self) -> ::std::result::Result<crate::types::AggregateOperation, ::aws_smithy_types::error::operation::BuildError> {
        ::std::result::Result::Ok(crate::types::AggregateOperation {
            column: self.column.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "column",
                    "column was not specified but it is required when building AggregateOperation",
                )
            })?,
            agg_func: self.agg_func.ok_or_else(|| {
                ::aws_smithy_types::error::operation::BuildError::missing_field(
                    "agg_func",
                    "agg_func was not specified but it is required when building AggregateOperation",
                )
            })?,
        })
    }