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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def build_attachment2():
 """Build attachment mock."""

    attachment = Attachment()
    attachment.content = "BwdW"
    attachment.type = "image/png"
    attachment.filename = "banner.png"
    attachment.disposition = "inline"
    attachment.content_id = "Banner"
    return attachment