text: total = {
  	_id: "YYYY-MM_DOMAIN_LAYER_REGISER",
  	value: {
  			period: 'YYYY-MM',
  			domain: 'company_id',
  			layer: 'layer_id',
  			register: 'ACC_ID|customer_ID|project_ID|cost_category',
  			totals:{
  					'USD':{
  							'dt': 241.22,
  							'ct': 244.12,
  					},
  					'EUR':{
  							'dt': 184.21,
  							'ct': 188.03
  					}
  			},
  	}
  }
  
  /*
   * 1. standard period is a month (easy to change to any period)
   * 2. only dt and ct turnover totals are stored; b/f and c/f 
   *    balances are calculated dynamically at each request
   * 3. there may be several layers within a domain, eg
   *    'fin_data','debtors_creditors','projects' etc, depending
   *    on the needs of particular application
   * 4. the notion of 'base currency' is not reflected in the 
   *    data structure: totals are grouped by commodity id (the
   *    paradigm was stolen from ledger cli project)
   * 5. 
   *
  */
  