'Initialise an instance.
:param metadata: An instance of :class:`Metadata` which describes the
distribution. This will normally have been initialised
from a metadata file in the ``path``.
:param path:     The path of the ``.dist-info`` or ``.egg-info``
directory for the distribution.
:param env:      This is normally the :class:`DistributionPath`
instance where this distribution was found.'

def __init__(self, metadata, path, env=None):

    super(BaseInstalledDistribution, self).__init__(metadata)
    self.path = path
    self.dist_path = env
