anchor.diff:  
   Also note that the model should refresh automatically, as that is the 
   nature of working with model-views in (py)qt.
  +
  +== Execute
  +=== UI: btn_execute
  +This section will describe the most important step: processing the table-data.
  +Processing will calculate missing or extra values and writes it all to the
  +correct tables in the database.
  +
  +=== Code: btn_execute_click
  +[btn_execute_click, python]
  +---
  +    self.ctl.write_to_database(self.model_data) #<1>
  +    self.set_lbl_check(self.ctl.get_check_info([])) #<2>
  +    self.model_data.clear() #<3>
  +---
  +<1> The main processing is started from this function in the controller.
  +<2> Detailed info that is displayed, will change after processing. An example
  +of this, is the total pool.
  +<3> After processing, the table-data is cleared again.
  +
  +=== Code: write_to_database
  +This code will do the following:
  +- load the classes for currency_exchange, rate, finance and trade.
  +- get the input_fields
  +- process currency_exchange: get statements, print them and write them to the db
  +- process rate: get statements, print them and write them to the db
  +- process finance: get statements, print them and write them to the db
  +- process trade: get statements, print them and write them to the db
  +
  +==== Code: get_input_fields
  +[write_to_database, python]
  +---
  +  
  +---
  
positive.code: 
  [[btnadd]]
  == Adding a transaction line
  === UI action
  This section describes what happens, if we enter data in the input fields and
  press the 'add'-button.
  Note: this only adds the input as a transaction line to the table-model in pyqt.
  
negative.code: 
  [[btnremove]]
  == Removing a transaction line
  === UI: btn_remove / btn_remove_last
  This section describes the functionality between the remove and remove_last buttons.
  Remove_last will remove the last entry from the table-model.
  Remove will remove the currently selected entry from the table-model.
  