Implement ET_Email_SendDefinition

[thureos]

Is your feature request related to a problem? Please describe
I can't send emails to a data extension, PHP SDK has this implemented.

Describe the solution you'd like
An implementation of ET_Email_SendDefinition

Describe alternatives you've considered
Port the code in PHP and try to run it

[bdgp1990]

Would be really nice !

[Thom3435]

@bdgp1990 add the following to your objects.py file

class ET_EmailSendDefinition(ET_CUDSupport):
    def __init__(self):
        super(ET_EmailSendDefinition, self).__init__()
        self.obj_type = 'EmailSendDefinition'