code: def get_savename_from_varname(
          varname, varname_prefix=None,
          savename_prefix=None):
      
      name = varname
      if varname_prefix is not None \
              and name.startswith(varname_prefix):
          name = name[len(varname_prefix) + 1:]
      if savename_prefix is not None:
          name = savename_prefix + '/' + name
      return name
docs: Args:
          varname(str): a variable name in the graph
          varname_prefix(str): an optional prefix that may need to be removed in varname
          savename_prefix(str): an optional prefix to append to all savename
      Returns:
          str: the name used to save the variable