import json
d = {'a': 'aaa', 'b': ['b1', 'b2', 'b3'], 'c': 100}
json_str = json.dumps(d)
print json_str

import json
class Customer:
  def __init__(self, name, grade, age, home, office):
    self.name = name
    self.grade = grade
    self.age = age
    self.address = Address(home, office)
  def __repr__(self):
    return repr((self.name, self.grade, self.age, self.address.home, self.address.office))
class Address:
  def __init__(self, home, office):
    self.home = home
    self.office = office
  def __repr__(self):
    return repr((self.name, self.grade, self.age))
customers = [
    Customer('john', 'A', 15, '111', 'aaa'),
    Customer('jane', 'B', 12, '222', 'bbb'),
    Customer('dave', 'B', 10, '333', 'ccc'),
    ]
json_str = json.dumps(customers, default=lambda o: o.__dict__, sort_keys=True, indent=4)
print json_str

[
  {
    "address": {
      "home": "111",
      "office": "aaa"
    },
    "age": 15,
    "grade": "A",
    "name": "john"
  },
  {
    "address": {
      "home": "222",
      "office": "bbb"
    },
    "age": 12,
    "grade": "B",
    "name": "jane"
  },
  {
    "address": {
      "home": "333",
      "office": "ccc"
    },
    "age": 10,
    "grade": "B",
    "name": "dave"
  }
]