code: def spherical_jn(n, z, derivative=False):
      r"""Spherical Bessel function of the first kind or its derivative.
  
      Defined as [1]_,
  
      .. math:: j_n(z) = \sqrt{\frac{\pi}{2z}} J_{n + 1/2}(z),
  
      where :math:`J_n` is the Bessel function of the first kind.
  
      Parameters
      ----------
      n : int, array_like
          Order of the Bessel function (n >= 0).
      z : complex or float, array_like
          Argument of the Bessel function.
      derivative : bool, optional
          If True, the value of the derivative (rather than the function
          itself) is returned.
  
      Returns
      -------
      jn : ndarray
  
      Notes
      -----
      For real arguments greater than the order, the function is computed
      using the ascending recurrence [2]_.  For small real or complex
      arguments, the definitional relation to the cylindrical Bessel function
      of the first kind is used.
  
      The derivative is computed using the relations [3]_,
  
      .. math::
          j_n'(z) = j_{n-1}(z) - \frac{n + 1}{z} j_n(z).
  
          j_0'(z) = -j_1(z)
  
  
      .. versionadded:: 0.18.0
  
      References
      ----------
      .. [1] https://dlmf.nist.gov/10.47.E3
      .. [2] https://dlmf.nist.gov/10.51.E1
      .. [3] https://dlmf.nist.gov/10.51.E2
      """
      if derivative:
          return _spherical_jn_d(n, z)
      else:
          return _spherical_jn(n, z)
  
imports: from __future__ import division, print_function, absolute_import
  from ._ufuncs import _spherical_jn, _spherical_yn, _spherical_in, _spherical_kn, _spherical_jn_d, _spherical_yn_d, _spherical_in_d, _spherical_kn_d
label_desc: Use image node_id 1 for calling a global function with example usage: spherical_jn(n, z, derivative) and returns: _spherical_jn_d, _spherical_jn