from pyfo import pyfo

input_request = \
('request',
 [('protocol-version', '3.00'),
    ('request-type', 2),
    ('terminal-id', '8357530'),
    ('extra', 'vasya', {'name': 'login'}),
    ('extra', '123', {'name': 'password'}),
    ('extra', 'Dealer v1.9',  {'name': 'client-software'}),
    ('transaction-number', '1012740131'),
    ('from', ""),
    ('to',
        [('service-id', '1'),
        ('accaunt-number', '9174807967'),
        ('amount', '28.50', {'currency-code': '810'}),
    ]),
    ('receipt',
        [('datetime', '20060322115752'),
        ('receipt-number', '740131'),
    ])
 ])

result = pyfo(input_request, pretty=True, prolog=True, encoding='windows-1251')
print result

<?xml version="1.0" encoding="windows-1251"?>
<request>
  <protocol-version>3.00</protocol-version>
  <request-type>2</request-type>
  <terminal-id>8357530</terminal-id>
  <extra name="login">vasya</extra>
  <extra name="password">123</extra>
  <extra name="client-software">Dealer v1.9</extra>
  <transaction-number>1012740131</transaction-number>
  <from/>
  <to>
    <service-id>1</service-id>
    <accaunt-number>9174807967</accaunt-number>
    <amount currency-code="810">28.50</amount>
  </to>
  <receipt>
    <datetime>20060322115752</datetime>
    <receipt-number>740131</receipt-number>
  </receipt>
</request>