title: How to configure authorization mechanism inline with boto3
body: <p>I am using boto3 in aws lambda to fecth object in S3 located in Frankfurt Region.</p>
  
  <p>v4 is necessary. otherwise following error will return</p>
  
  <pre><code>"errorMessage": "An error occurred (InvalidRequest) when calling 
  the GetObject operation: The authorization mechanism you have 
  provided is not supported. Please use AWS4-HMAC-SHA256."
  </code></pre>
  
  <p>Realized ways to configure signature_version <a href="http://boto3.readthedocs.org/en/latest/guide/configuration.html" rel="noreferrer">http://boto3.readthedocs.org/en/latest/guide/configuration.html</a></p>
  
  <p>But since I am using AWS lambda, I do not have access to underlying configuration profiles</p>
  
  <p>The code of my AWS lambda function </p>
  
  <pre><code>from __future__ import print_function
  import boto3
  
  
  def lambda_handler (event, context):
      input_file_bucket = event["Records"][0]["s3"]["bucket"]["name"]
      input_file_key = event["Records"][0]["s3"]["object"]["key"]
      input_file_name = input_file_bucket+"/"+input_file_key
  
      s3=boto3.resource("s3")
      obj = s3.Object(bucket_name=input_file_bucket, key=input_file_key)
      response = obj.get()
      return event #echo first key valuesdf
  </code></pre>
  
  <p>Is that possible to configure signature_version within this code ? use Session for example. Or is there any workaround on this?</p>