code: def normal_cdf(x):
      """Cumulative distribution function for a standard normal distribution."""
      return 0.5 + 0.5 * np.vectorize(math.erf)(x / math.sqrt(2))
  
imports: import math
  import numpy
  from tensorflow.python.ops.distributions import special_math
label_desc: Use image node_id 3 for calling a global function with example usage: normal_cdf(x) and returns: unknown