code: def load_header_chain( cls, chain_path ):
          
  
          header_parser = BlockHeaderSerializer()
          chain = []
          height = 0
          with open(chain_path, "rb") as f:
  
              h = SPVClient.read_header_at( f )
              h['block_height'] = height 
  
              height += 1
              chain.append(h)
  
          return chain
docs: Load the header chain from disk.
          Each chain element will be a dictionary with:
          *