code: def gammamomentcond2(distfn, params, mom2, quantile=None):
      """estimate distribution parameters based method of moments (mean,
      variance) for distributions with 1 shape parameter and fixed loc=0.
  
      Returns
      -------
      difference : ndarray
          difference between theoretical and empirical moments
  
      Notes
      -----
      first test version, quantile argument not used
  
      The only difference to previous function is return type.
  
      """
      alpha, scale = params
      mom2s = distfn.stats(alpha, 0.0, scale)
      return np.array(mom2) - mom2s
  
file_path: statsmodels/statsmodels/sandbox/distributions/estimators.py
imports: import numpy
  from scipy import stats, optimize, special
label_desc: Use image node_id 2 for calling a global function with example usage: gammamomentcond2(distfn, params, mom2, quantile) and returns: unknown