code: def _validate_var(self, var):
          
          if "/" in var:
              filt, rest = var.split("/")
              if "|" in rest:
                  varname, prop = rest.split("|")
                  return prop != ""
              elif rest == "timing":
                  return True
              else:
                  return False
          else:
              return True
docs: Validates the *form* only of the specified variable.