code: def _mod(a, b):
      """C-style modulo function"""
      if b == 0:
          # Javascript returns NaN in cases of division by 0; return -1 because
          # None would fail comparisons with other ints
          return float("nan")
      d = trunc(float(a) / b)
      return a - d * b
  
imports: import numpy
  from math import floor, ceil, trunc
  from ._constants import COLUMN_SEPARATOR_STRING
  from .libpsppy import get_data_slice_unit, get_data_slice_zero, get_data_slice_one, get_data_slice_two, get_from_data_slice_unit, get_from_data_slice_zero, get_from_data_slice_one, get_from_data_slice_two, get_pkeys_from_data_slice_unit, get_pkeys_from_data_slice_zero, get_pkeys_from_data_slice_one, get_pkeys_from_data_slice_two, scalar_to_py
label_desc: Use image node_id 1 for calling a global function with example usage: _mod(a, b) and returns: unknown, float