[FIX] do not raise error if pybarcode is not installed

barcodes_generate/models/barcode_generate_mixin.py

@@ -4,10 +4,18 @@
 # @author: Sylvain LE GAL (https://twitter.com/legalsylvain)
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 
-import barcode
+import logging
 
 from openerp import models, fields, api, exceptions
 
+_logger = logging.getLogger(__name__)
+
+try:
+    import barcode
+except ImportError:
+    _logger.debug("Cannot import 'barcode' python Librairy.")
+    barcode = None
+
 
 class barcode_generate_mixin(models.AbstractModel):
     _name = 'barcode.generate.mixin'