input: Write a function to estimate the value of π using the Monte Carlo method.
  assert round(estimate_pi(1000000), 2) in [3.13, 3.14, 3.15]
  assert round(estimate_pi(500000), 2) in [3.13, 3.14, 3.15]
  assert round(estimate_pi(100000), 1) in [3.1, 3.2]
output: import random
  
  def estimate_pi(num_samples):
      inside_circle = 0
      for _ in range(num_samples):
          x, y = random.uniform(0, 1), random.uniform(0, 1)
          if x**2 + y**2 <= 1:
              inside_circle += 1
      return (inside_circle / num_samples) * 4