code: def _compute_log_a_int(q: float, sigma: int, alpha: int) -> float:
      """Compute log(A_alpha) for integer alpha. 0 < q < 1."""
      assert isinstance(alpha, six.integer_types)
  
      # Initialize with 0 in the log space.
      log_a = -np.inf
  
      for i in range(alpha + 1):
          log_coef_i = (
              _log_comb(alpha, i)
              + i * math.log(q)
              + (alpha - i) * math.log(1 - q)
          )
  
          s = log_coef_i + (i * i - i) / (2 * (sigma**2))
          log_a = _log_add(log_a, s)
  
      return float(log_a)
  
imports: import math
  from typing import Tuple, Union
  import numpy
  from scipy import special
  import six
label_desc: Use image node_id 5 for calling a global function with example usage: _compute_log_a_int(q, sigma, alpha) and returns: float