diff --git a/invoice.py b/invoice.py
index 2a1928e..845fd90 100644
--- a/invoice.py
+++ b/invoice.py
@@ -1,7 +1,5 @@
-from trytond.pool import Pool, PoolMeta
-from trytond.model import ModelView, fields
-from trytond.exceptions import UserError
-from trytond.pyson  import Eval
+from trytond.pool import PoolMeta
+from trytond.pyson import Eval
 
 
 class InvoiceLine(metaclass=PoolMeta):
@@ -13,4 +11,3 @@ class InvoiceLine(metaclass=PoolMeta):
 
         cls.product.states['required'] = (Eval('type') == 'line')
         cls.unit_price.domain = []
-
diff --git a/product.py b/product.py
index d46777f..a8edb39 100644
--- a/product.py
+++ b/product.py
@@ -1,6 +1,6 @@
-from trytond.pool import Pool, PoolMeta
+from trytond.pool import PoolMeta
 from trytond.model import fields
-from trytond.pyson import Eval, Bool
+from trytond.pyson import Eval
 
 
 class Product(metaclass=PoolMeta):
diff --git a/production.py b/production.py
index 2896984..01ce45e 100644
--- a/production.py
+++ b/production.py
@@ -1,12 +1,8 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
 from decimal import Decimal
-
 from trytond.pool import Pool, PoolMeta
 from trytond.model import fields
-from trytond.modules.product import price_digits, round_price
-
-from trytond.exceptions import UserError
 
 
 BOM_CHANGES = ['bom', 'product', 'quantity', 'uom', 'warehouse', 'location',
@@ -37,15 +33,17 @@ class Production(metaclass=PoolMeta):
             move = self._explode_move_values('input', input_, quantity)
             if move:
                 inputs.append(move)
-                quantity = Uom.compute_qty(input_.uom, quantity,
-                                           input_.product.default_uom, round=False)
+                quantity = Uom.compute_qty(
+                    input_.uom, quantity,
+                    input_.product.default_uom, round=False)
             # else:
             #     quantity = input_.compute_quantity(factor)
             #     move = self._explode_move_values('output', input_, quantity)
             #     if move:
             #         inputs.append(move)
-            #         quantity = Uom.compute_qty(input_.uom, quantity,
-            #                                    input_.product.default_uom, round=False)
+            #         quantity = Uom.compute_qty(
+                # input_.uom, quantity,
+            #   input_.product.default_uom, round=False)
         self.inputs = inputs
 
         outputs = []
diff --git a/user.py b/user.py
index 5409ec7..c56b70b 100644
--- a/user.py
+++ b/user.py
@@ -1,5 +1,6 @@
 from trytond.model import fields
-from trytond.pool import Pool, PoolMeta
+from trytond.pool import PoolMeta
+
 
 class User(metaclass=PoolMeta):
     "User"