old_contents: from marshmallow import Schema, fields
  
  
  class PetSchema(Schema):
      description = dict(id="Pet id", name="Pet name")
      id = fields.Int(dump_only=True, description=description['id'])
      name = fields.Str(description=description['name'], required=True, deprecated=False, allowEmptyValue=False)
  
  
  class SampleSchema(Schema):
      runs = fields.Nested('RunSchema', many=True, exclude=('sample',))
  
      count = fields.Int()
  
  
  class RunSchema(Schema):
      sample = fields.Nested(SampleSchema, exclude=('runs',))
  
  
  class AnalysisSchema(Schema):
      sample = fields.Nested(SampleSchema)
  
  
  class AnalysisWithListSchema(Schema):
      samples = fields.List(fields.Nested(SampleSchema))
  
  
  class PatternedObjectSchema(Schema):
      count = fields.Int(dump_only=True, **{'x-count': 1})
      count2 = fields.Int(dump_only=True, x_count2=2)
  
  
  class SelfReferencingSchema(Schema):
      id = fields.Int()
      single = fields.Nested('self')
      single_with_ref = fields.Nested('self', ref='#/definitions/Self')
      many = fields.Nested('self', many=True)
      many_with_ref = fields.Nested('self', many=True, ref='#/definitions/Selves')
  
  
  class OrderedSchema(Schema):
      field1 = fields.Int()
      field2 = fields.Int()
      field3 = fields.Int()
      field4 = fields.Int()
      field5 = fields.Int()
  
      class Meta:
          ordered = True
  
  
  class DefaultCallableSchema(Schema):
      numbers = fields.List(fields.Int, missing=list)
  
new_contents: from marshmallow import Schema, fields
  
  
  class PetSchema(Schema):
      description = dict(id='Pet id', name='Pet name')
      id = fields.Int(dump_only=True, description=description['id'])
      name = fields.Str(description=description['name'], required=True, deprecated=False, allowEmptyValue=False)
  
  
  class SampleSchema(Schema):
      runs = fields.Nested('RunSchema', many=True, exclude=('sample',))
  
      count = fields.Int()
  
  
  class RunSchema(Schema):
      sample = fields.Nested(SampleSchema, exclude=('runs',))
  
  
  class AnalysisSchema(Schema):
      sample = fields.Nested(SampleSchema)
  
  
  class AnalysisWithListSchema(Schema):
      samples = fields.List(fields.Nested(SampleSchema))
  
  
  class PatternedObjectSchema(Schema):
      count = fields.Int(dump_only=True, **{'x-count': 1})
      count2 = fields.Int(dump_only=True, x_count2=2)
  
  
  class SelfReferencingSchema(Schema):
      id = fields.Int()
      single = fields.Nested('self')
      single_with_ref = fields.Nested('self', ref='#/definitions/Self')
      many = fields.Nested('self', many=True)
      many_with_ref = fields.Nested('self', many=True, ref='#/definitions/Selves')
  
  
  class OrderedSchema(Schema):
      field1 = fields.Int()
      field2 = fields.Int()
      field3 = fields.Int()
      field4 = fields.Int()
      field5 = fields.Int()
  
      class Meta:
          ordered = True
  
  
  class DefaultCallableSchema(Schema):
      numbers = fields.List(fields.Int, missing=list)
  
subject: fix style