input: Write a function to convert the given temperature from Celsius to Fahrenheit. If the given temperature is in Celsius, return the equivalent 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