input: Write a function called slicing that takes a string and two integers representing the start and end indices, and returns the substring formed by slicing the given string from the start index to the end index (not inclusive).
  
  assert slicing("This is a slicing test", 8, 15)=="slicing"
  assert slicing("Python programming", 7, 18)=="programming"
  assert slicing("Hello World", 6, 11)=="World"
  assert slicing("Coding is fun", 0, 6)=="Coding"
  assert slicing("Short example", 11, 12)==""
output: def slicing(s, start, end):
      return s[start:end]