code: def funbgh(s, a, b, R, df):
      sqrt_df = np.sqrt(df + 0.5)
      ret = chi_logpdf(s, df)
      ret += np_log(
          mvstdnormcdf(
              s * a / sqrt_df,
              s * b / sqrt_df,
              R,
              maxpts=1000000,
              abseps=1e-6,
          )
      )
      ret = np_exp(ret)
      return ret
  
file_path: statsmodels/statsmodels/sandbox/distributions/multivariate.py
imports: import numpy
  from scipy import integrate, stats, special
  from scipy.stats import chi
  from .extras import mvstdnormcdf
  from numpy import exp
  from numpy import log
  from scipy.special import gamma
  from scipy.special import gammaln
label_desc: Use image node_id 4 for calling a global function with example usage: funbgh(s, a, b, R, df) and returns: ret