input: Write a function to perform string slicing in Python that takes a string and start and end indices as input, and returns the substring between these indices. If the indices are invalid or out of range, return an empty string. The function should be named 'slicing'.
  
  assert slicing("This is a slicing test", 8, 15) == "a slicing"
  assert slicing("Hello, World!", 7, 12) == "World"
  assert slicing("Python", 10, 15) == ""
  assert slicing("", 0, 0) == ""
  assert slicing("Short", -3, 2) == ""
output: def slicing(s, start, end):
      if start < 0 or end > len(s) or start >= end:
          return ""
      return s[start:end]