code: def safe_round(number, ndigits):
      ret = None
      if number is not None:
          ret = round(number, ndigits)
      return ret
  
imports: from six.moves import xrange
  from .None import common
  from pyalgotrade.technical import ma
  from pyalgotrade import dataseries
  from pyalgotrade.barfeed import ninjatraderfeed
  from pyalgotrade import bar
label_desc: Use image node_id 1 for calling a global function with example usage: safe_round(number, ndigits) and returns: ret