Users want to get rounding mode in `quantileExact` equivalent to "median_low" from Python:
https://docs.python.org/3/library/statistics.html#statistics.median_low
while current implementation works equivalent to "median_high" (?)
#include <AggregateFunctions/AggregateFunctionQuantile.h>
#include <AggregateFunctions/AggregateFunctionFactory.h>
#include <AggregateFunctions/Helpers.h>
#include <Core/Field.h>
#include "registerAggregateFunctions.h"
namespace DB
{
namespace ErrorCodes
{
    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
namespace
{
template <typename Value, bool float_return> using FuncQuantile = AggregateFunctionQuantile<Value, QuantileReservoirSampler<Value>, NameQuantile, false, std::conditional_t<float_return, Float64, void>, false>;
template <typename Value, bool float_return> using FuncQuantiles = AggregateFunctionQuantile<Value, QuantileReservoirSampler<Value>, NameQuantiles, false, std::conditional_t<float_return, Float64, void>, true>;
template <typename Value, bool float_return> using FuncQuantileDeterministic = AggregateFunctionQuantile<Value, QuantileReservoirSamplerDeterministic<Value>, NameQuantileDeterministic, true, std::conditional_t<float_return, Float64, void>, false>;
template <typename Value, bool float_return> using FuncQuantilesDeterministic = AggregateFunctionQuantile<Value, QuantileReservoirSamplerDeterministic<Value>, NameQuantilesDeterministic, true, std::conditional_t<float_return, Float64, void>, true>;
template <typename Value, bool _> using FuncQuantileExact = AggregateFunctionQuantile<Value, QuantileExact<Value>, NameQuantileExact, false, void, false>;
template <typename Value, bool _> using FuncQuantilesExact = AggregateFunctionQuantile<Value, QuantileExact<Value>, NameQuantilesExact, false, void, true>;
template <typename Value, bool _> using FuncQuantileExactExclusive = AggregateFunctionQuantile<Value, QuantileExactExclusive<Value>, NameQuantileExactExclusive, false, Float64, false>;
template <typename Value, bool _> using FuncQuantilesExactExclusive = AggregateFunctionQuantile<Value, QuantileExactExclusive<Value>, NameQuantilesExactExclusive, false, Float64, true>;
template <typename Value, bool _> using FuncQuantileExactInclusive = AggregateFunctionQuantile<Value, QuantileExactInclusive<Value>, NameQuantileExactInclusive, false, Float64, false>;
template <typename Value, bool _> using FuncQuantilesExactInclusive = AggregateFunctionQuantile<Value, QuantileExactInclusive<Value>, NameQuantilesExactInclusive, false, Float64, true>;
template <typename Value, bool _> using FuncQuantileExactWeighted = AggregateFunctionQuantile<Value, QuantileExactWeighted<Value>, NameQuantileExactWeighted, true, void, false>;
template <typename Value, bool _> using FuncQuantilesExactWeighted = AggregateFunctionQuantile<Value, QuantileExactWeighted<Value>, NameQuantilesExactWeighted, true, void, true>;