input: 
  def filter_out_negative(matrix):
      """ Filters out all negative numbers from the given matrix and returns the modified matrix.
      >>> filter_out_negative([[-1, 2, -3], [-4, 5, 6], [-7, 8, 9]])
      array([[0, 2, 0],
             [0, 5, 6],
             [0, 8, 9]])
      """
  
output:     import numpy as np
      matrix = np.array(matrix)
      matrix[matrix < 0] = 0
      return matrix