The technique used in this and the remaining methods are all
pretty basic use of the SQLAlchemy Query class.
# - - - M y C B C . g e n C i r s
def genCirs(self):
'''Generate all circles, ascending by lat-lon.
'''
#-- 1 --
# [ q := a Session.Query to retrieve all rows of self.Cir ]
q = self.s.query(self.Cir)
#-- 2 --
# [ generate the rows in q ]
for row in q:
yield row