def set_campaign_merge(targets, campaign_id)
    login! unless logged_in?
    json = <<-EOF
      {
        "session": "#{@sugar_session_id}",
        "targets": #{targets.to_json},
        "campaign-id": "#{campaign_id}"
      }
    EOF
    json.gsub!(/^\s{6}/,'')
    send!(:set_campaign_merge, json)
  end
def set_campaign_merge(targets, campaign_id)
    login! unless logged_in?
    json = <<-EOF
      {
        "session": "#{@sugar_session_id}",
        "targets": #{targets.to_json},
        "campaign-id": "#{campaign_id}"
      }
    EOF
    json.gsub!(/^\s{6}/,'')
    send!(:set_campaign_merge, json)
  end
Performs a mail merge for the specified campaign.