def initiate_layer_upload(registryId=None, repositoryName=None):
    """
    Notify Amazon ECR that you intend to upload an image layer.
    See also: AWS API Documentation
    
    
    :example: response = client.initiate_layer_upload(
        registryId='string',
        repositoryName='string'
    )
    
    
    :type registryId: string
    :param registryId: The AWS account ID associated with the registry that you intend to upload layers to. If you do not specify a registry, the default registry is assumed.

    :type repositoryName: string
    :param repositoryName: [REQUIRED]
            The name of the repository that you intend to upload layers to.
            

    :rtype: dict
    :return: {
        'uploadId': 'string',
        'partSize': 123
    }
    
    
    """
    pass
