input: Write a function to slice a string in Python that takes a string and start and end indices, and returns the slice of the string from the start index to the end index (exclusive). If the start or end index is out of bounds, return an empty string.
  
  assert slicing("This is a slicing test", 8, 15)=="slicing"
  assert slicing("This is a slicing test", 0, 4)=="This"
  assert slicing("This is a slicing test", 20, 25)==""
  assert slicing("This is a slicing test", 5, 0)==""
output: def slicing(s, start, end):
      if start < 0 or end < 0 or start >= len(s) or end > len(s) or start >= end:
          return ""
      return s[start:end]