input: Write a python function to create a complex vector and print it in a readable format.
  assert str(ComplexVector("1 - 2i")) == "1.0 + -2.0i"
  assert str(ComplexVector("3 + 4i")) == "3.0 + 4.0i"
  assert str(ComplexVector("5.5 - 6.6i")) == "5.5 + -6.6i"
output: def ComplexVector(complex_str):
      complex_str = complex_str.replace('i', '')
      real_part, imag_part = map(float, complex_str.split())
      return f"{real_part} + {imag_part}i"