code: def __execute_bsh(self, instr):
          
          op0_val = self.read_operand(instr.operands[0])
          op1_val = self.read_operand(instr.operands[1])
  
          op1_size = instr.operands[1].size
  
          # Check sign bit.
          if extract_sign_bit(op1_val, op1_size) == 0:
              op2_val = op0_val << op1_val
          else:
              op2_val = op0_val >> twos_complement(op1_val, op1_size)
  
          self.write_operand(instr.operands[2], op2_val)
  
          return None
docs: Execute BSH instruction.