code: def diff(a, n=1, axis=-1, prepend=None, append=None):
      """Calculate the n-th discrete difference along the given axis.
  
      Args:
          a (cupy.ndarray): Input array.
          n (int): The number of times values are differenced. If zero, the input
              is returned as-is.
          axis (int): The axis along which the difference is taken, default is
              the last axis.
          prepend (int, float, cupy.ndarray): Value to prepend to ``a``.
          append (int, float, cupy.ndarray): Value to append to ``a``.
  
      Returns:
          cupy.ndarray: The result array.
  
      .. seealso:: :func:`numpy.diff`
      """
  
      if n == 0:
          return a
      if n < 0:
          raise ValueError(
              "order must be non-negative but got " + repr(n)
          )
  
      a = cupy.asanyarray(a)
      nd = a.ndim
      axis = internal._normalize_axis_index(axis, nd)
  
      combined = []
  
      if prepend is not None:
          prepend = cupy.asanyarray(prepend)
          if prepend.ndim == 0:
              shape = list(a.shape)
              shape[axis] = 1
              prepend = cupy.broadcast_to(prepend, tuple(shape))
          combined.append(prepend)
  
      combined.append(a)
  
      if append is not None:
          append = cupy.asanyarray(append)
          if append.ndim == 0:
              shape = list(a.shape)
              shape[axis] = 1
              append = cupy.broadcast_to(append, tuple(shape))
          combined.append(append)
  
      if len(combined) > 1:
          a = cupy.concatenate(combined, axis)
  
      slice1 = [slice(None)] * nd
      slice2 = [slice(None)] * nd
      slice1[axis] = slice(1, None)
      slice2[axis] = slice(None, -1)
      slice1 = tuple(slice1)
      slice2 = tuple(slice2)
  
      op = cupy.not_equal if a.dtype == numpy.bool_ else cupy.subtract
      for _ in range(n):
          a = op(a[slice1], a[slice2])
  
      return a
  
imports: import warnings
  import numpy
  import cupy
  from cupy._core import _routines_math
  from cupy._core import _fusion_thread_local
  from cupy._core import internal
label_desc: Use image node_id 10 for calling a global function with example usage: diff(a, n, axis, prepend, append) and returns: a, a