docs: def addBlock(self,branch=None,btype=None,mtype=None,attributes=None):
          '''
          Add block definition to list of blocks in material
          Order for list entry: branch level (0=root), block type (material,solid,fluid,etc.), matid (integer if root, False otherwise),
              material name (string if root, False otherwise), material type, dictionary of attributes or False if none
          '''
          if branch == 0:
              attributes = self.attributes
          blk = {'branch': branch,
                 'btype': btype,
                 'mtype': mtype,
                 'attributes': attributes}
          
          self.blocks.append(blk)