input: Write a python function to calculate the roots of a quadratic equation.
  assert calculate_roots(1, -7, 10) == (5.0, 2.0)
  assert calculate_roots(1, 0, -4) == (2.0, -2.0)
  assert calculate_roots(1, 4, 4) == (-2.0, -2.0)
  assert calculate_roots(1, 1, 1) == "The equation has no real solutions."
output: def calculate_roots(a, b, c):
      import cmath
      discriminant = b**2 - 4*a*c
      if discriminant < 0:
          return "The equation has no real solutions."
      root1 = (-b + cmath.sqrt(discriminant).real) / (2 * a)
      root2 = (-b - cmath.sqrt(discriminant).real) / (2 * a)
      return (root1, root2)