old_contents: from oemof.core.energy_system import Region
  
  
  class RegionDingo(Region):
      """
      Defines a region in DINGO, derived from oemof
      ----------------------------
  
      """
      def __init__(self, **kwargs):
          #inherit parameters from oemof's Region
          super().__init__(**kwargs)
  
          #more params
          self.id_db = kwargs.get('id_db', None)
  
  
new_contents: from oemof.core.energy_system import Region
  
  
  class RegionDingo(Region):
      """
      Defines a region in DINGO, derived from oemof
      ---------------------------------------------
  
      """
      def __init__(self, **kwargs):
          #inherit parameters from oemof's Region
          super().__init__(**kwargs)
  
          #more params
          self.id_db = kwargs.get('id_db', None)
  
  
  class RegionCentreDingo:
      """
      Defines a region centre in Dingo
      --------------------------------
      The centres are used in the MV routing as nodes.
      Note: Centre is a point within a region's polygon that is located most central (e.g. in a simple region shape like a
      circle it's the geometric center).
  
      Parameters
      ----------
      id_db: unique ID in database (=id of associated load area)
      """
      def __init__(self, **kwargs):
          self.id_db = kwargs.get('id_db', None)
  
      def __repr__(self):
          return 'regioncentre_' + str(self.id_db)
subject: add class RegionCentreDingo for routing (part of #51)