def create_blocks(message, download_link=''):
    """
    Create blocks for the main message, a divider, and context that links to Shipyard.
    If a download link is provided, creates a button block to immediately start that download.
    For more information: https://api.slack.com/block-kit/building
    """

    message_section = {
        "type": "section",
        "text": {
            "type": "mrkdwn",
            "text": message,
            "verbatim": True
        }
    }
    divider_section = {
        "type": "divider"
    }

    if download_link != '':
        download_section = {
            "type": "actions",
            "elements": [
                {
                    "type": "button",
                    "text": {
                        "type": "plain_text",
                        "text": "Download File"
                    },
                    "value": "file_download",
                    "url": download_link,
                    "style": "primary"
                }
            ]
        }
        blocks = [message_section, download_section,
                  divider_section]
    else:
        blocks = [message_section, divider_section]

    return blocks