code: def ndig(a, b):
      """Precision for NIST values."""
      return round(
          -math.log10((abs(abs(a) - abs(b)) + 1.0e-15) / abs(b))
      )
  
imports: import math
  from optparse import OptionParser
  from numpy.testing import assert_allclose
  from lmfit import Parameters, minimize
  from .NISTModels import Models, ReadNistData
label_desc: Use image node_id 1 for calling a global function with example usage: ndig(a, b) and returns: round