message: Allow whitespace after commas in hparam strings.
  E.g., allow 'a=b, c=d' or 'a=b,\nc=d' in addition to just 'a=b,c=d'.
diff: @@ -40,7 +40,7 @@ PARAM_RE = re.compile(r"""
  ((?P<val>[^,\[]*) # single value: "a" or None
  |
  \[(?P<vals>[^\]]*)\]) # list of values: None or "1,2,3"
  - ($|,)""", re.VERBOSE)
  + ($|,\s*)""", re.VERBOSE)
  def _parse_fail(name, var_type, value, values):
  