old_contents: import numpy as np
  
  def get_l2fc(a, b):
      return np.log2(b + 1) - np.log2(a + 1)
  
new_contents: import numpy as np
  
  def l2fc(a, b):
      """
      Calculate the log2 Fold Change between two arrays, floats, or integers
      a and b cannot be, nor contain, values less than 0
  
      :param (int/float/np.array) a: Value or array
      :param (int/float/np.array) b: Value or array
      :return: L2FC array or value
      :rtype: (int/float/np.array)
      """
      return np.log2(a + 1) - np.log2(b + 1)
  
subject: Add l2fc docstring