Minor fix

message.xml

@@ -61,7 +61,10 @@ this repository contains the full copyright notices and license terms. -->
             <field name="text">Missing account debit or credit for statement journal "%(s)s"</field>
         </record>
         <record model="ir.message" id="msg_missing_code_product">
-            <field name="text">Missing code for product.</field>
+            <field name="text">Missing code for product</field>
+        </record>
+        <record model="ir.message" id="msg_previous_statement_open">
+            <field name="text">There is previous statement current open. Please close it!</field>
         </record>
     </data>
 </tryton>

statement.py

@@ -4,6 +4,7 @@
 from datetime import date, datetime
 from decimal import Decimal
 from dateutil import tz
+
 from trytond.model import fields, ModelView, ModelSQL, Workflow
 from trytond.pool import Pool, PoolMeta
 from trytond.transaction import Transaction
@@ -11,6 +12,7 @@ from trytond.wizard import Button, StateTransition, StateView, Wizard
 from trytond.pyson import Eval
 from trytond.i18n import gettext
 from .exceptions import StatementValidationError
+from trytond.exceptions import UserError
 
 _ZERO = Decimal("0.0")
 
@@ -335,9 +337,9 @@ class OpenStatement(Wizard):
     start = StateView(
         'open.statement.start',
         'sale_pos.open_statement_start', [
-          Button('Cancel', 'end', 'tryton-cancel'),
-          Button('Ok', 'create_', 'tryton-ok', default=True),
-    ])
+            Button('Cancel', 'end', 'tryton-cancel'),
+            Button('Ok', 'create_', 'tryton-ok', default=True),
+        ])
     create_ = StateTransition()
     done = StateView(
         'open.statement.done',
@@ -352,7 +354,16 @@ class OpenStatement(Wizard):
     def default_done(self, fields):
         return {
             'result': self.result,
-            }
+        }
+
+    def _check_previous(self, sale_device, today):
+        pool = Pool()
+        Statement = pool.get('account.statement')
+        res = Statement.search_read([
+            ('sale_device', '=', sale_device.id),
+            ('state', '=', 'draft'),
+            ], fields_names=['id'])
+        return res
 
     def transition_create_(self):
         pool = Pool()
@@ -368,6 +379,15 @@ class OpenStatement(Wizard):
         user = Transaction().user
         user = User(user)
         device = user.sale_device
+        time_zone = company.timezone
+        now_ = datetime.now(tz.gettz(time_zone))
+        today = date(now_.year, now_.month, now_.day)
+        previous = self._check_previous(device, today)
+        print("res............", previous)
+        if previous:
+            raise UserError(
+                gettext('sale_pos.msg_previous_statement_open'))
+            return 'end'
         if device:
             journals = [j.id for j in device.journals]
             statements = Statement.search([
@@ -376,14 +396,13 @@ class OpenStatement(Wizard):
                 ], order=[
                 ('date', 'ASC'),
             ])
-            journals_of_draft_statements = [s.journal for s in statements
-                                            if s.state == 'draft']
+            journals_of_draft_statements = [
+                s.journal for s in statements if s.state == 'draft'
+            ]
 
             vlist = []
             result = ''
-            time_zone = company.timezone
-            now_ = datetime.now(tz.gettz(time_zone))
-            today = date(now_.year, now_.month, now_.day)
+
             for journal in device.journals:
                 statements_today = Statement.search([
                     ('journal', '=', journal.id),