input: Write a python function to calculate the total amount of energy generated per hour by a wind turbine.
  assert calculate_energy(100, 10) == 500000.0
  assert calculate_energy(50, 5) == 3125.0
  assert calculate_energy(200, 8) == 409600.0
output: def calculate_energy(wind_speed, blade_length):
      air_density = 1.225  # kg/m^3
      swept_area = 3.14159 * (blade_length ** 2)  # m^2
      power_coefficient = 0.4  # coefficient of performance
      power = 0.5 * air_density * swept_area * (wind_speed ** 3) * power_coefficient  # in watts
      energy_per_hour = power * 3600  # converting power (watts) to energy (joules) per hour
      return energy_per_hour