Connecting to MS SQL Server with Windows Authentication using Python?

How do I connect MS SQL Server using Windows Authentication, with the pyodbc library?

I can connect via MS Access and SQL Server Management Studio, but cannot get a working connection ODBC string for Python.

Here's what I've tried (also without 'Trusted_Connection=yes'):

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}', server='[system_name]',
               database='[databasename]')

pyodbc.connect('Trusted_Connection=yes', uid='me',
               driver='{SQL Server}', server='localhost',
               database='[databasename]')

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}', server='localhost',
               uid='me', pwd='[windows_pass]', database='[database_name]')

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}', server='localhost',
               database='[server_name]\\[database_name]')

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}', server='localhost',
               database='[server_name]\[database_name]')

pyodbc.connect('Trusted_Connection=yes',
               driver='{SQL Server}',
               database='[server_name]\[database_name]')

You can specify the connection string as one long string that uses semi-colons (;) as the argument separator.

Working example:

import pyodbc
cnxn = pyodbc.connect(r'Driver=SQL Server;Server=.\SQLEXPRESS;Database=myDB;Trusted_Connection=yes;')
cursor = cnxn.cursor()
cursor.execute("SELECT LastName FROM myContacts")
while 1:
    row = cursor.fetchone()
    if not row:
        break
    print(row.LastName)
cnxn.close()

For connection strings with lots of parameters, the following will accomplish the same thing but in a somewhat more readable way:

conn_str = (
    r'Driver=SQL Server;'
    r'Server=.\SQLEXPRESS;'
    r'Database=myDB;'
    r'Trusted_Connection=yes;'
    )
cnxn = pyodbc.connect(conn_str)

(Note that there are no commas between the individual string components.)