input: Write a function to filter out all negative numbers from the given matrix and replace them with zeros. Return the modified matrix.
  import numpy as np
  
  def filter_out_negative(matrix):
    # Convert matrix to numpy array
    matrix = np.array(matrix)
    # Find all negative numbers and set them to 0
    matrix[matrix < 0] = 0
    return matrix
  
  assert np.array_equal(filter_out_negative([[-1, 2, -3], [-4, 5, 6], [-7, 8, 9]]), [[0, 2, 0], [0, 5, 6], [0, 8, 9]])
  assert np.array_equal(filter_out_negative([[1, -2, 3], [-4, -5, 6], [7, 8, -9]]), [[1, 0, 3], [0, 0, 6], [7, 8, 0]])
  assert np.array_equal(filter_out_negative([[-1, -2, -3], [-4, -5, -6], [-7, -8, -9]]), [[0, 0, 0], [0, 0, 0], [0, 0, 0]])
  assert np.array_equal(filter_out_negative([[0, 1, 2], [3, 4, 5], [6, 7, 8]]), [[0, 1, 2], [3, 4, 5], [6, 7, 8]])
  assert np.array_equal(filter_out_negative([]), np.array([]))
output: 
  def filter_out_negative(matrix):
    matrix = np.array(matrix)
    matrix[matrix < 0] = 0
    return matrix
  