@marqh you forgot to add the parentheses to the `upper` call i.e. `upper()`.

How's about a minor refactor:
 * Create a module level constant, say `_ENV_PREFIX = "metarelate"`
 * Set `env_var` as follows `env_var = '{}_{}'.format(_ENV_PREFIX, 'static_dir')
 * Remove the use of the `option` variable

Also see the following comment below.