Hua Rong Dao - 华容道 (Klotski) solver

Written in 100% python, this program calculates the best possible sequence of moves to solve the puzzle

Note: Each 'Move' is one unit in any direction
example:

How the game of 华容道 works

Hua Rong Dao is a very old Chinese game, where you slide pieces to get the 'General'
the largest (2 x 2) piece to the exit at the bottom of the board. You cannot jump over any piece or
remove any piece from the board.

Some common/custom starting positions