code: def load(self, filename, bs=512):
          
          with open(filename, 'rb') as f:
              f.seek(GPT_HEADER_OFFSET + 0x0C)
              header_size = struct.unpack("<I", f.read(4))[0]
              f.seek(GPT_HEADER_OFFSET)
  
              header_data = f.read(header_size)
              self.header = GPT_HEADER(header_data)
  
              if (self.header.signature != GPT_SIGNATURE):
                  raise Exception("Invalid GPT signature")
  
              self.__load_partition_entries(f, bs)
docs: Loads GPT partition table.
  
          Args:
              filename (str): path to file or device to open for reading
              bs (uint): Block size of the volume, default: 512
  
          Raises:
              IOError: If file does not exist or not readable