feat(generator): handle multiple response codes per operation (#73)

## Description

Support OpenAPI specs having multiple status codes per operation.

Author: aplumez

exoscale/api/generator.py

@@ -52,8 +52,7 @@ def _get_ref(api_spec, path):
 }
 
 
-def _return_docstring(api_spec, operation):
-    [status_code] = operation["responses"].keys()
+def _status_code_docstring(api_spec, operation, status_code):
     [ctype] = operation["responses"][status_code]["content"].keys()
     return_schema = operation["responses"][status_code]["content"][ctype][
         "schema"
@@ -96,6 +95,17 @@ def _return_docstring(api_spec, operation):
     return doc
 
 
+def _return_docstring(api_spec, operation):
+    status_codes_docs = [
+        "{status_code}: {ret_type}".format(
+            status_code=status_code,
+            ret_type=_status_code_docstring(api_spec, operation, status_code),
+        )
+        for status_code in operation["responses"].keys()
+    ]
+
+    return "\n        ".join(status_codes_docs)
+
 class BaseClient:
     _api_spec = None
     _by_operation = None