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: context.rb
    path of file: ./repos/mongo-ruby-driver/lib/mongo/crypt
    
    the code of the file until where you have to start completion: # frozen_string_literal: true
# rubocop:todo all

# Copyright (C) 2019-2020 MongoDB Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the Licen
    
      def mongocrypt_feed(doc)
        Binding.ctx_mongo_feed(self, doc)
      end

      # Retrieves KMS credentials for providers that are configured
      # for automatic credentials retrieval.
      #
      # @return [ Crypt::KMS::Credentials ] Credentials for the configured
      #   KMS providers.
      def retrieve_kms_credentials
        providers = {}
        if kms_providers.aws&.empty?
          begin
            aws_credentials = Mongo::Auth::Aws::CredentialsRetriever.new.credentials
          rescue Auth::Aws::CredentialsNotFound
            raise Error::CryptError.new(
              "Could not locate AWS credentials (checked environment variables, ECS and EC2 metadata)"
            )
          end
          providers[:aws] = aws_credentials.to_h
        end