take PricePerUnit from customer if not set in invoice position

src/main.py

@@ -86,13 +86,16 @@ def main():
 
         print('Envelope data:')
         envelope_data = DataObject(**envelope)
-        print(envelope_data.__dict__)
+        print('<--->')
+        print(yaml.dump(envelope_data))
+        print('</--->')
 
         print('Invoice data:')
         invoice_data = DataObject(**invoice)
         merge_envelope_data_into_invoice_data(invoice_data, envelope_data.Invoice)
 
-        selected_customer = next((x for x in envelope_data.Customers if x['CustomerId'] == invoice_data.CustomerId), None)
+        selected_customer = next((x for x in envelope_data.Customers if x['CustomerId'] == invoice_data.CustomerId),
+                                 None)
         merge_envelope_data_into_invoice_data(invoice_data, selected_customer)
 
         if not hasattr(invoice_data, 'InvoiceDate'):
@@ -103,8 +106,17 @@ def main():
         if not hasattr(invoice_data, 'Id'):
             invoice_data.Id = None
 
+        if not hasattr(invoice_data, 'Positions'):
+            invoice_data.Positions = []
+
+        for position in invoice_data.Positions:
+            if 'PricePerUnit' not in position or position['PricePerUnit'] is None:
+                position['PricePerUnit'] = invoice_data.PricePerUnit
+
         invoice_data.Id = invoice_data.Id or invoice_file.stem
-        print(invoice_data.__dict__)
+        print('<--->')
+        print(yaml.dump(invoice_data))
+        print('</--->')
 
     except FileNotFoundError as e:
         print(f'Error: {e}')
@@ -119,8 +131,6 @@ def main():
     generator = html_generator.HtmlTemplate(args.template)
     template = generator.prepare_template(invoice_data, envelope_data)
 
-    print(template)
-
     try:
         print('Generating invoice...')
         invoice_pdf = Path(invoice_data.Id).with_suffix('.pdf')