<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def file_content(self, value):
 """The Base64 encoded content of the attachment :param value: The Base64 encoded content of the attachment :type value: FileContent, string """

        if isinstance(value, FileContent):
            self._file_content = value
        else:
            self._file_content = FileContent(value)