'Sets account metadata.  A call to this will add to the account
metadata and not overwrite all of it with values in the metadata dict.
To clear an account metadata value, pass an empty string as
the value for the key in the metadata dict.
:param account: Account on which to get the metadata.
:param metadata: Dict of metadata to set.
:param metadata_prefix: Prefix used to set metadata values in headers
of requests, used to prefix keys in metadata
when setting metadata, defaults to \'\'.
:param acceptable_statuses: List of status for valid responses,
defaults to (2,).
:raises UnexpectedResponse: Exception raised when requests fail
to get a response with an acceptable status
:raises Exception: Exception is raised when code fails in an
unexpected way.'

def set_account_metadata(self, account, metadata, metadata_prefix='', acceptable_statuses=(2,)):

    path = self.make_path(account)
    self._set_metadata(path, metadata, metadata_prefix, acceptable_statuses)
