using .json file instead of .yaml after set_config_type('yaml')

[malefs]

I set reading config from type 'yaml' and set the config name
in the config-directory i have two files 1. calc_config.yaml and 2. calc_config.json
vyper reads in the calc_config.json instead the calc_config.yaml.

v.set_config_type('yaml')
v.set_config_name("calc_config")
v.read_in_config()