driver-core/src/main/com/mongodb/client/model/Accumulators.java
public static <TExpression> BsonField stdDevPop(final String fieldName, final TExpression expression) {
        return accumulator("$stdDevPop", fieldName, expression);
    }
public static <TExpression> BsonField stdDevPop(final String fieldName, final TExpression expression) {
        return accumulator("$stdDevPop", fieldName, expression);
    }
Gets a field name for a $group operation representing the sample standard deviation of the values of the given expression
when applied to all members of the group.

<p>Use if the values encompass the entire population of data you want to represent and do not wish to generalize about
a larger population.</p>

@param fieldName the field name
@param expression the expression
@param <TExpression> the expression type
@return the field
@mongodb.driver.manual reference/operator/aggregation/stdDevPop/ $stdDevPop
@mongodb.server.release 3.2
@since 3.2