code: def lanczos_sum(x):
      num = 0.0
      den = 0.0
  
      if x < 5.0:
          for i in range(LANCZOS_N - 1, -1, -1):
              num = num * x + lanczos_num_coeffs[i]
              den = den * x + lanczos_den_coeffs[i]
      else:
          for i in range(LANCZOS_N):
              num = num / x + lanczos_num_coeffs[i]
              den = den / x + lanczos_den_coeffs[i]
  
      return num / den
  
imports: from typing import Optional, Union, Tuple, List, Sequence
  import numpy
  import numpy.typing
  import ivy
  from ivy import promote_types_of_inputs
  from ivy.functional.backends.numpy.helpers import _scalar_output_to_0d_array
  from ivy.func_wrapper import with_unsupported_dtypes
  from .None import backend_version
label_desc: Use image node_id 25 for calling a global function with example usage: lanczos_sum(x) and returns: unknown