class_docstr: Class Feature Interpreter.
  
  The class is used to generate the following information:
      - feature distribution
      - feature correlation
      - feature importance ranking for a trained model
docstr: Internal function to calculate correlation among numerical features
  
  Args:
      df: Dataframe
      numerical_cols: list, list of numerical columns
      correlation_type: str, pre-defined correlation type
  
  Returns:
      A dictionary maps two column names to correlation type and value
docstr_tok: ["Internal","function","to","calculate","correlation","among","numerical","features","Args",":","df",":","Dataframe","numerical_cols",":","list",",","list","of","numerical","columns","correlation_type",":","str",",","pre-defined","correlation","type","Returns",":","A","dictionary","maps","two","column","names","to","correlation","type","and","value"]
code: def _get_numerical_correlation(
      self, df, numerical_cols, correlation_type
  ) -> Dict[Tuple[str, str], Tuple[str, float]]:
      """
      Internal function to calculate correlation among numerical features
  
      Args:
          df: Dataframe
          numerical_cols: list, list of numerical columns
          correlation_type: str, pre-defined correlation type
  
      Returns:
          A dictionary maps two column names to correlation type and value
  
      """
      if correlation_type not in ["pearson", "kendall", "spearman"]:
          raise UnsupportedMethodType(correlation_type)
      corr = df[numerical_cols].corr(method=correlation_type)
      correlations = dict()
      for col_a in numerical_cols:
          for col_b in numerical_cols:
              correlations[(col_a, col_b)] = (
                  correlation_type,
                  corr[col_a][col_b],
              )
      return correlations
  
imports: import operator
  import warnings
  import numpy
  import pandas
  from scipy import stats
  from typing import List, Dict, Tuple
  import shap
  from xai import ALG, MODE
  from xai.data.constants import DATATYPE
  from xai.data.explorer.data_analyzer_suite import DataAnalyzerSuite
  from xai.model.interpreter.exceptions import InconsistentSize, TrainingDataNotProvided
  from xai.model.interpreter.exceptions import UnsupportedMethodType
label_desc: Use image node_id 5 for calling the FeatureInterpreter obj's underlying member method code with example usage: obj._get_numerical_correlation(df, numerical_cols, correlation_type) and returns: correlations