input: Write a function to convert the given temperature from Celsius to Fahrenheit. The function should take a temperature in Celsius as input and return the corresponding temperature in Fahrenheit.
  assert celsius_to_fahrenheit(0)==32.0
  assert celsius_to_fahrenheit(100)==212.0
  assert celsius_to_fahrenheit(-40)==-40.0
  assert celsius_to_fahrenheit(25)==77.0
  assert celsius_to_fahrenheit(37)==98.6
output: def celsius_to_fahrenheit(celsius):
      return (celsius * 9/5) + 32