input: Write a python function to remove outliers using the interquartile range (IQR) method.
  assert np.array_equal(remove_outliers(np.array([1, 2, 3, 4, 100, 101])), np.array([1, 2, 3, 4]))
  assert np.array_equal(remove_outliers(np.array([10, 20, 30, 40, 50, 1000])), np.array([10, 20, 30, 40, 50]))
  assert np.array_equal(remove_outliers(np.array([5, 7, 8, 5, 2, 15, 20])), np.array([5, 7, 8, 5, 2, 15]))
output: import numpy as np
  
  def remove_outliers(data):
      q1 = np.percentile(data, 25)
      q3 = np.percentile(data, 75)
      iqr = q3 - q1
      lower_bound = q1 - 1.5 * iqr
      upper_bound = q3 + 1.5 * iqr
      return data[(data >= lower_bound) & (data <= upper_bound)]