use super::super::helpers::{aggregations, comparison_ops, math_ops, string_ops, window_ops};
use super::super::merge;
use super::super::trait_def::PandasCompatExt;
use super::super::types::{Axis, CorrelationMatrix, DescribeStats, RankMethod, SeriesValue};
use crate::dataframe::base::DataFrame;
use crate::series::Series;
use std::collections::{HashMap, HashSet};