code: def product_two_guassian_pdfs(mu_1, sigma_1, mu_2, sigma_2):
      """Product of two Guasssian PDF."""
      # https://ccrma.stanford.edu/~jos/sasp/Product_Two_Gaussian_PDFs.html
      sigma_1_square = tf.square(sigma_1)
      sigma_2_square = tf.square(sigma_2)
      mu = (mu_1 * sigma_2_square + mu_2 * sigma_1_square) / (
          sigma_1_square + sigma_2_square
      )
      sigma_square = (sigma_1_square * sigma_2_square) / (
          sigma_1_square + sigma_2_square
      )
      sigma = tf.sqrt(sigma_square)
      return mu, sigma
  
imports: import numpy
  import sonnet
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling a global function with example usage: product_two_guassian_pdfs(mu_1, sigma_1, mu_2, sigma_2) and returns: mu,  sigma