Convert a list to a comma separated string, within a dict

frankenjinja.j2

{%- macro recurse_dict(data) -%}
  {%- set topdict = {} -%}
  {%- for k,v in data.iteritems() %}
      {%- if v is mapping -%}
          {%- do topdict.update({ k: recurse_dict(v) }) -%}
      {%- elif v is iterable and v is not string -%}
          {%- set list_as_str = v | join(',') -%}
          {%- do topdict.update({ k: list_as_str }) -%}
      {%- else -%}
          {%- do topdict.update({ k: v }) -%}
      {%- endif -%}
  {%- endfor -%}
  {{ topdict }}
{%- endmacro -%}
vars: {{ recurse_dict(salt['pillar.get']('sensu:vars')) }}

thing.py

def recurse_dict(data):
    topdict = {}
    for k,v in data.items():
        if isinstance(v, dict):
            topdict[k] = recurse_dict(v)
        elif isinstance(v, list):
            list_as_str = ','.join(v)
            topdict[k] = list_as_str
        else:
            topdict[k] = v
    return topdict

working.py

# yay!
def stringify_dict_list(pillar_path):
    def recurse_dict(data):
        topdict = {}
        for k,v in data.items():
            if isinstance(v, dict):
                topdict[k] = recurse_dict(v)
            elif isinstance(v, list):
                list_as_str = ','.join(v)
                topdict[k] = list_as_str
            else:
                topdict[k] = v
        return topdict

    data = __salt__['pillar.get'](pillar_path, {})
    return recurse_dict(data)

Please don't judge me.