<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _integer_to_interval(arg, unit='s'):
 """ Convert integer interval with the same inner type Parameters unit : {'Y', 'M', 'W', 'D', 'h', 'm', s', 'ms', 'us', 'ns'} Returns ------- interval : interval value expression """

    op = ops.IntervalFromInteger(arg, unit)
    return op.to_expr()