Fix bug in list_instruments when module arg is absent

Author: natezb

instrumental/drivers/__init__.py

@@ -739,12 +739,15 @@ def list_instruments(server=None, module=None, blacklist=None):
     try:
         import visa
         try:
-            inst_list = [p for p in list_visa_instruments() if module in p['module']]
+            inst_list = list_visa_instruments()
         except visa.VisaIOError:
             inst_list = []  # Hide visa errors
     except (ImportError, ConfigError):
         inst_list = []  # Ignore if PyVISA not installed or configured
 
+    if module:
+        inst_list = [p for p in list_visa_instruments() if module in p['module']]
+
     for mod_name in driver_info:
         if module and module not in mod_name:
             continue