code: def splder(tck, n=1):
      """
      Compute the spline representation of the derivative of a given spline
  
      Parameters
      ----------
      tck : BSpline instance or a tuple of (t, c, k)
          Spline whose derivative to compute
      n : int, optional
          Order of derivative to evaluate. Default: 1
  
      Returns
      -------
      `BSpline` instance or tuple
          Spline of order k2=k-n representing the derivative
          of the input spline.
          A tuple is returned iff the input argument `tck` is a tuple, otherwise
          a BSpline object is constructed and returned.
  
      Notes
      -----
  
      .. versionadded:: 0.13.0
  
      See Also
      --------
      splantider, splev, spalde
      BSpline
  
      Examples
      --------
      This can be used for finding maxima of a curve:
  
      >>> from scipy.interpolate import splrep, splder, sproot
      >>> x = np.linspace(0, 10, 70)
      >>> y = np.sin(x)
      >>> spl = splrep(x, y, k=4)
  
      Now, differentiate the spline and find the zeros of the
      derivative. (NB: `sproot` only works for order 3 splines, so we
      fit an order 4 spline):
  
      >>> dspl = splder(spl)
      >>> sproot(dspl) / np.pi
      array([ 0.50000001,  1.5       ,  2.49999998])
  
      This agrees well with roots :math:`\\pi/2 + n\\pi` of
      :math:`\\cos(x) = \\sin'(x)`.
  
      """
      if isinstance(tck, BSpline):
          return tck.derivative(n)
      else:
          return _impl.splder(tck, n)
  
file_path: catboost/contrib/python/scipy/py2/scipy/interpolate/fitpack.py
imports: from __future__ import print_function, division, absolute_import
  import warnings
  import numpy
  from ._fitpack_impl import bisplrep, bisplev, dblint
  from .None import _fitpack_impl
  from ._bsplines import BSpline
label_desc: Use image node_id 8 for calling a global function with example usage: splder(tck, n) and returns: tck, _impl