input: Write a function to perform string slicing that takes a string and start and end index, and returns the slice. If the start index is greater than the end index, return an empty string.
  
  def slicing(string, start, end):
      if start > end:
          return ""
      return string[start:end]
  
  assert slicing("This is a test string", 5, 7) == "is"
  assert slicing("Python is great", 0, 4) == "Pyth"
  assert slicing("Short string", 10, 3) == ""
  assert slicing("", 2, 5) == ""
  assert slicing("Long string example", 10, 15) == "ring "
output: def slicing(string, start, end):
      if start > end:
          return ""
      return string[start:end]