code: def _size2units(size):
      """Convert the size returned from _get_pos_units into a physical unit."""
      if size >= 0.050 and size < 0.500:
          unit = "m"
          sf = 1
      elif size >= 0.50 and size < 5:
          unit = "dm"
          sf = 10
      elif size >= 5 and size < 50:
          unit = "cm"
          sf = 100
      elif size >= 50 and size < 500:
          unit = "mm"
          sf = 1000
      else:
          unit = "unknown"
          sf = 1
  
      return unit, sf
  
imports: from copy import deepcopy
  import numpy
  from ...utils import logger
label_desc: Use image node_id 4 for calling a global function with example usage: _size2units(size) and returns: unit,  sf