code: def alpha_calc(RACC, ACC, POP):
      """
      Calculate Unweighted Krippendorff's alpha.
  
      :param RACC: random accuracy
      :type RACC: float
      :param ACC: accuracy
      :type ACC: float
      :param POP: population or total number of samples
      :type POP: int
      :return: unweighted alpha as float
      """
      try:
          epsi = 1 / (2 * POP)
          p_a = (1 - epsi) * ACC + epsi
          p_e = RACC
          return reliability_calc(p_e, p_a)
      except Exception:
          return "None"
  
imports: from __future__ import division
  import math
  import operator
  from functools import reduce
  from .pycm_interpret import *
  from .pycm_ci import kappa_SE_calc, CI_calc, SE_calc
  from .pycm_util import complement
label_desc: Use image node_id 4 for calling a global function with example usage: alpha_calc(RACC, ACC, POP) and returns: reliability_calc, str