code: def zeta(ctx, s, a=1, derivative=0, method=None, **kwargs):
      d = int(derivative)
      if a == 1 and not (d or method):
          try:
              return ctx._zeta(s, **kwargs)
          except NotImplementedError:
              pass
      s = ctx.convert(s)
      prec = ctx.prec
      method = kwargs.get("method")
      verbose = kwargs.get("verbose")
      if (not s) and (not derivative):
          return ctx.mpf(0.5) - ctx._convert_param(a)[0]
      if a == 1 and method != "euler-maclaurin":
          im = abs(ctx._im(s))
          re = abs(ctx._re(s))
          # if (im < prec or method == 'borwein') and not derivative:
          #    try:
          #        if verbose:
          #            print "zeta: Attempting to use the Borwein algorithm"
          #        return ctx._zeta(s, **kwargs)
          #    except NotImplementedError:
          #        if verbose:
          #            print "zeta: Could not use the Borwein algorithm"
          #        pass
          if (
              abs(im) > 500 * prec
              and 10 * re < prec
              and derivative <= 4
              or method == "riemann-siegel"
          ):
              try:  #  py2.4 compatible try block
                  try:
                      if verbose:
                          print(
                              "zeta: Attempting to use the Riemann-Siegel algorithm"
                          )
                      return ctx.rs_zeta(s, derivative, **kwargs)
                  except NotImplementedError:
                      if verbose:
                          print(
                              "zeta: Could not use the Riemann-Siegel algorithm"
                          )
                      pass
              finally:
                  ctx.prec = prec
      if s == 1:
          return ctx.inf
      abss = abs(s)
      if abss == ctx.inf:
          if ctx.re(s) == ctx.inf:
              if d == 0:
                  return ctx.one
              return ctx.zero
          return s * 0
      elif ctx.isnan(abss):
          return 1 / s
      if ctx.re(s) > 2 * ctx.prec and a == 1 and not derivative:
          return ctx.one + ctx.power(2, -s)
      return +ctx._hurwitz(s, a, d, **kwargs)
  
imports: from __future__ import print_function
  from ..libmp.backend import xrange
  from .functions import defun, defun_wrapped, defun_static
label_desc: Use image node_id 23 for calling a global function with example usage: zeta(ctx, s, a, derivative, method) and returns: unknown, unknown, ctx, unknown, unknown, ctx, ctx, unknown, ctx, ctx