code: def rand_student_t(df, mu=0, std=1):
      """
      return random number distributed by student's t distribution with
      `df` degrees of freedom with the specified mean and standard deviation.
      """
  
      x = random.gauss(0, std)
      y = 2.0 * random.gammavariate(0.5 * df, 2.0)
      return x / (math.sqrt(y / df)) + mu
  
imports: from __future__ import absolute_import, division, unicode_literals
  import math
  from math import cos, sin
  import random
  import warnings
  import numpy
  from numpy.linalg import inv
  import scipy.linalg
  import scipy.sparse
  import scipy.sparse.linalg
  from scipy.stats import norm, multivariate_normal
label_desc: Use image node_id 24 for calling a global function with example usage: rand_student_t(df, mu, std) and returns: unknown