def get_credentials():
    """
    Returns the value stored in the AWS_ACCESS_KEY_ID environment variable and
    the value stored in the AWS_SECRET_ACCESS_KEY environment variable.

    Returns
    -------
    out : tuple [string]
        The first string of the tuple is the value of the AWS_ACCESS_KEY_ID
        environment variable. The second string of the tuple is the value of the
        AWS_SECRET_ACCESS_KEY environment variable.

    See Also
    --------
    set_credentials
    http://boto.cloudhackers.com/en/latest/boto_config_tut.html

    Examples
    --------
    >>> get_credentials()
    ('RBZH792CTQPP7T435BGQ', '7x2hMqplWsLpU/qQCN6xAPKcmWo46TlPJXYTvKcv')
    """
    from boto.s3.connection import S3Connection
    from boto.exception import NoAuthHandlerFound
    try:
        conn = S3Connection()
    except NoAuthHandlerFound:
        raise RuntimeError(
            'No AWS access credentials found. Please set the environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY or see http://boto.cloudhackers.com/en/latest/boto_config_tut.html for other options in configuring AWS.'
            )
    return conn.access_key, conn.secret_key
