code: def add(self, child, name=None, coordinates=None):
          
          if not name:
              name = str(child)
  
          if name in self.children_by_name:
              raise RuntimeWarning(
                  'Child with name {} already in slot, use custom name'.format(
                      name))
  
          if coordinates:
              child._coordinates = Vector(coordinates)
          child.parent = self
          self.children_by_name[name] = child
          self.children_by_reference[child] = name
docs: Adds child to the :Placeable:, storing it's :name: and :coordinates:
  
          This method is used to add :Well:s to the :Container:,
          add :Slot:s to :Deck:, etc