code: public void assignAmounts(XTrace trace, Map<String, Double> amounts) {
  		XCostAmount.instance().assignValues(trace, amounts);
  	}
docs: Assigns (to the given trace) multiple amounts given their keys. Note that
  as a side effect this method creates attributes when it does not find an
  attribute with the proper key.
  
  For example, the call:
  
  <pre>
  assignAmounts(trace, [[a 10.00] [b 15.00] [c 25.00]])
  </pre>
  
  should result into the following XES fragment:
  
  <pre>
  {@code
  <trace>
  <string key="a" value="">
  <float key="cost:amount" value="10.00"/>
  </string>
  <string key="b" value="">
  <float key="cost:amount" value="15.00"/>
  </string>
  <string key="c" value="">
  <float key="cost:amount" value="25.00"/>
  </string>
  </trace>
  }
  </pre>
  
  @param trace
  Trace to assign the amounts to.
  @param amounts
  Mapping from keys to amounts which are to be assigned.