[Mgmt][Botservice] multi inheritance problem

• Package Name: azure-mgmt-boservice
• Package Version: 2.0.0b2
• Operating System: Linux/Windows
• Python Version: 3.7.0

Describe the bug
When initialize model Site, the following error will be raised:

>       super(WebChatSite, self).__init__(**kwargs)
E       TypeError: __init__() missing 2 required keyword-only arguments: 'site_name' and 'is_enabled'

To Reproduce
Steps to reproduce the behavior:
run the following code:

from azure.mgmt.botservice.models import Site

Site(
    is_v1_enabled=True,
    is_v3_enabled=True,
    site_name="xxx",
    is_enabled=True,
    is_webchat_preview_enabled=True,
    is_secure_site_enabled=True
)

Expected behavior
The model could be initialized successfully

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Additional context
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