error

Error: Could not retrieve catalog from remote server: Error 400 on SERVER: Failed to parse template uwsgi/uwsgi.ini.erb:
  Filepath: /etc/puppet/modules/uwsgi/templates/uwsgi.ini.erb
  Line: 16
  Detail: undefined method `sort_by' for #<String:0x2a4870f8>
 at /etc/puppet/modules/uwsgi/manifests/init.pp:148 on node node.domain.com
Warning: Not using cache on failed catalog
Error: Could not retrieve catalog; skipping run

hiera.yaml

uwsgi::emperor_options:
  log-master = 'true'
  log-reopen = 'true'
  log-4xx = 'true'
  log-5xx = 'true'
  log-zero = 'true'
  touch-logreopen = 'true'

uwsgi.ini.erb

#
# This file is managed by puppet class 'uwsgi'
#
# uWSGI main process configuration
#
[uwsgi]
socket = <%= @socket %>
pidfile = <%= @pidfile %>
emperor = <%= @app_directory %>
emperor-tyrant = <%= @tyrant %>
master = true
autoload = true
log-date = true
logto = <%= @log_file %>
<%- if @emperor_options -%>
<%- @emperor_options.sort_by{|k,v| k}.each do |key, value| -%>
<%= key %> = <%= value %>
<%- end -%>
<%- end -%>

uwsgi.pp

class uwsgi (
   ...
   $emperor_options = undef

) {
   # stuff
}