input: Write a python function to find the points where the sum of cosine and sine equals zero.
  assert np.allclose(find_zeros(-2*np.pi, 2*np.pi, 0.5), [-4.71238898, 1.57079633])
  assert np.allclose(find_zeros(-4*np.pi, 4*np.pi, 0.5), [-10.99557429, -4.71238898, 1.57079633, 7.85398163])
  assert np.allclose(find_zeros(-np.pi, np.pi, 0.1), [-1.57079633])
output: import numpy as np
  
  def find_zeros(start, end, step):
      def func(x):
          return np.sin(x) + np.cos(x)
      
      zeros = []
      x = start
      while x <= end:
          if np.isclose(func(x), 0, atol=1e-5):
              zeros.append(x)
          x += step
      
      return zeros