<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_block_manager_axis(cls, axis):
 """Map the axis to the block_manager axis."""

        axis = cls._get_axis_number(axis)
        if cls._AXIS_REVERSED:
            m = cls._AXIS_LEN - 1
            return m - axis
        return axis