diff --git a/invoice.py b/invoice.py
index cf1d14b..a81c02d 100644
--- a/invoice.py
+++ b/invoice.py
@@ -1,29 +1,40 @@
 # 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 trytond.pool import Pool, PoolMeta
-from trytond.model import ModelView, ModelSQL, fields
+from trytond.pool import PoolMeta
+from trytond.model import fields
 from trytond.modules.currency.fields import Monetary
-
-from trytond.exceptions import UserError
-
 from decimal import Decimal
+from trytond.model.exceptions import ValidationError
+
 
 class InvoiceLine(metaclass=PoolMeta):
     'Invoice Line Extras'
     __name__ = 'account.invoice.line'
 
-    tax_amount = fields.Function(Monetary("Tax", currency='currency', digits='currency'),
+    tax_amount = fields.Function(Monetary("Tax",
+                                          currency='currency',
+                                          digits='currency'),
                                  'get_amount_taxes')
-    tax_unit = fields.Function(Monetary("Unit Tax", currency='currency', digits='currency'),
-                                 'get_unit_taxes')
-    total_with_taxes = fields.Function(Monetary("Total With Taxes", currency='currency', digits='currency'),
+    tax_unit = fields.Function(Monetary("Unit Tax",
+                                        currency='currency',
+                                        digits='currency'),
+                               'get_unit_taxes')
+    total_with_taxes = fields.Function(Monetary("Total With Taxes",
+                                                currency='currency',
+                                                digits='currency'),
                                        'get_total_with_taxes')
-    unit_with_tax = fields.Function(Monetary("Unit With Tax", currency='currency', digits='currency'),
-                                       'get_unit_with_tax')
-    tax_extra_unit = Monetary("Tax Extra Unit", currency='currency', digits='currency')
+    unit_with_tax = fields.Function(Monetary("Unit With Tax",
+                                             currency='currency',
+                                             digits='currency'),
+                                    'get_unit_with_tax')
+    tax_extra_unit = Monetary(
+        "Tax Extra Unit", currency='currency', digits='currency')
 
-    total_tax_extra = fields.Function(Monetary("Total Tax Extra", currency='currency', digits='currency'),
-                                         'get_total_tax_extra')
+    total_tax_extra = fields.Function(Monetary(
+        "Total Tax Extra",
+        currency='currency',
+        digits='currency'),
+        'get_total_tax_extra')
 
     @fields.depends('type', 'quantity', 'unit_price', 'unit', 'invoice',
                     '_parent_invoice.currency', 'taxes', 'amount')
@@ -39,7 +50,6 @@ class InvoiceLine(metaclass=PoolMeta):
             return tax_amount
         return Decimal('0.0')
 
-    
     @fields.depends('type', 'quantity', 'unit_price', 'unit', 'invoice',
                     '_parent_invoice.currency', 'taxes', 'amount')
     def on_change_with_tax_unit(self):
@@ -58,42 +68,47 @@ class InvoiceLine(metaclass=PoolMeta):
                     '_parent_invoice.currency', 'taxes', 'amount')
     def on_change_with_total_with_taxes(self):
         try:
-            total_with_taxes = self.amount + self.tax_amount    
+            total_with_taxes = self.amount + self.tax_amount
             return total_with_taxes
-        except:
-            pass
+        except Exception as e:
+            raise ValidationError(f"Se produjo un error {e}.")
 
-
-    @fields.depends('type', 'quantity', 'unit_price', 'unit', 'invoice',
-                    '_parent_invoice.currency', 'taxes', 'amount')
+    @fields.depends('type', 'quantity',
+                    'unit_price', 'unit',
+                    'invoice', '_parent_invoice.currency',
+                    'taxes', 'amount')
     def on_change_with_unit_with_tax(self):
         try:
-            unit_with_tax = self.unit_price + self.tax_unit    
+            unit_with_tax = self.unit_price + self.tax_unit
             return unit_with_tax
-        except:
-            pass
+        except Exception as e:
+            raise ValidationError(f"Se produjo un error {e}.")
 
-    @fields.depends('type', 'quantity', 'tax_extra_unit', 'unit_price', 'unit', 'invoice',
-                    '_parent_invoice.currency', 'taxes', 'amount')
+    @fields.depends('type', 'quantity', 'tax_extra_unit',
+                    'unit_price', 'unit', 'invoice',
+                    '_parent_invoice.currency',
+                    'taxes', 'amount')
     def on_change_with_total_tax_extra(self):
         if self.type == 'line':
             currency = self.invoice.currency if self.invoice else None
             total_tax_extra = Decimal(str(self.quantity or '0.0')) * \
-                    (self.tax_extra_unit or Decimal('0.0'))
+                (self.tax_extra_unit or Decimal('0.0'))
             if currency:
                 return currency.round(total_tax_extra)
             return total_tax_extra
         return Decimal('0.0')
 
-    @fields.depends('product', 'unit', '_parent_invoice.type',   
-        '_parent_invoice.party', 'party', 'invoice', 'invoice_type',
-        '_parent_invoice.invoice_date', '_parent_invoice.accounting_date',
-        'company', methods=['_get_tax_rule_pattern'])
+    @fields.depends('product', 'unit', '_parent_invoice.type',
+                    '_parent_invoice.party',
+                    'party', 'invoice', 'invoice_type',
+                    '_parent_invoice.invoice_date',
+                    '_parent_invoice.accounting_date',
+                    'company', methods=['_get_tax_rule_pattern'])
     def on_change_product(self):
         self.tax_amount = self.on_change_with_tax_amount()
         self.total_with_taxes = self.on_change_with_total_with_taxes()
-        super(Line, self).on_change_product()
-        
+        super(InvoiceLine, self).on_change_product()
+
     def get_amount_taxes(self, name):
         if self.type == 'line':
             return self.on_change_with_tax_amount()
@@ -105,7 +120,7 @@ class InvoiceLine(metaclass=PoolMeta):
     def get_total_with_taxes(self, name):
         if self.type == 'line':
             return self.on_change_with_total_with_taxes()
-        
+
     def get_unit_with_tax(self, name):
         if self.type == 'line':
             return self.on_change_with_unit_with_tax()
diff --git a/setup.py b/setup.py
index 8af7910..420134c 100755
--- a/setup.py
+++ b/setup.py
@@ -85,7 +85,8 @@ setup(name=name,
     download_url=download_url,
     project_urls={
         "Bug Tracker": 'https://bugs.tryton.org/',
-        "Documentation": 'https://docs.tryton.org/projects/modules-purchase-line-extras',
+        "Documentation":
+            'https://docs.tryton.org/projects/modules-purchase-line-extras',
         "Forum": 'https://www.tryton.org/forum',
         "Source Code": 'https://hg.tryton.org/modules/purchase_line_extras',
         },