fluent-python.py

# Fluent Interface Definition
class sql:
    class select:
        def __init__(self, dbcolumn, context=None):
            self.dbcolumn = dbcolumn
            self.context = context
        def select(self, dbcolumn):
            return self.__class__(dbcolumn,self)

# Demo
q = sql.select('foo').select('bar')
print q.dbcolumn  #bar
print q.context.dbcolumn  #foo