text: class SurfaceBase(object):
      """
      Increments the Line ID every time a new object is created that inherits
      from LineBase.
  
      Parameters
      ----------
      id0 : str
          If no unique ID is given, the object global is incremented.
      """
  
      _ID = 0
      num_edges = 0
      dimension = 2
  
      def __init__(self, id0=None, num_edges=0):
          if id0:
              assert isinstance(id0, str)
              self.id = id0
          else:
              self.id = "s{}".format(SurfaceBase._ID)
              SurfaceBase._ID += 1
          self.num_edges = num_edges
          return
  