docs: def add_unit(unit,**kwargs):
      """
          Add the unit defined into the object "unit" to the DB
          If unit["project_id"] is None it means that the unit is global, otherwise is property of a project
          If the unit exists emits an exception
  
  
          A minimal example:
  
          .. code-block:: python
  
              new_unit = dict(
  
                  name      = 'Teaspoons per second',
                  abbreviation = 'tsp s^-1',
                  cf        = 0,               # Constant conversion factor
                  lf        = 1.47867648e-05,  # Linear conversion factor
                  dimension_id = 2,
                  description  = 'A flow of one teaspoon per second.',
              )
              add_unit(new_unit)
  
  
      """
  
      new_unit = Unit()
      new_unit.dimension_id   = unit["dimension_id"]
      new_unit.name           = unit['name']
  
      # Needed to uniform abbr to abbreviation
      new_unit.abbreviation = unit['abbreviation']
  
      # Needed to uniform into to description
      new_unit.description = unit['description']
  
      new_unit.lf             = unit['lf']
      new_unit.cf             = unit['cf']
  
      if ('project_id' in unit) and (unit['project_id'] is not None):
          # Adding dimension to the "user" dimensions list
          new_unit.project_id = unit['project_id']
  
      # Save on DB
      db.DBSession.add(new_unit)
      db.DBSession.flush()
  
      return JSONObject(new_unit)