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: partition.rs
    path of file: ./repos/aws-sdk-rust/sdk/drs/src/endpoint_lib
    
    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.
/*
 *  Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *  SPDX-License-Identifier: Apache-2.0
 */

//! Partition function to determine a partition for a given region
//!
//! This function supports adding regions dynamically, parsing a JSON file, and
    
    pub(crate) fn deserialize_partitions(value: &[u8]) -> Result<PartitionResolver, DeserializeError> {
        let mut tokens_owned = json_token_iter(value).peekable();
        let tokens = &mut tokens_owned;
        expect_start_object(tokens.next())?;
        let mut resolver = None;
        loop {
            match tokens.next().transpose()? {
                Some(Token::EndObject { .. }) => break,
                Some(Token::ObjectKey { key, .. }) => match key.to_unescaped()?.as_ref() {
                    "partitions" => {
                        resolver = Some(PartitionResolver::from_partitions(deser_partitions(tokens)?));
                    }
                    _ => skip_value(tokens)?,
                },
                other => return Err(DeserializeError::custom(format!("expected object key or end object, found: {:?}", other))),
            }
        }
        if tokens.next().is_some() {
            return Err(DeserializeError::custom("found more JSON tokens after completing parsing"));
        }
        resolver.ok_or_else(|| DeserializeError::custom("did not find partitions array"))
    }