'init method for S3ReportStorage, Note that we have added an extra key-word
argument named "custom_domain" and this argument should not be passed to the superclass\'s init.
Args:
acl: content policy for the uploads i.e. private, public etc.
bucket: Name of S3 bucket to use for storing and/or retrieving content
custom_domain: custom domain to use for generating file urls
**settings: additional settings to be passed in to S3BotoStorage,
Returns:'

def __init__(self, acl=None, bucket=None, custom_domain=None, **settings):

    if custom_domain:
        self.custom_domain = custom_domain
    super(S3ReportStorage, self).__init__(acl=acl, bucket=bucket, **settings)
