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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 get(self, artifact):
 """Gets the coordinate with the correct version for the given artifact coordinate. :param M2Coordinate artifact: the coordinate to lookup. :return: a coordinate which is the same as the input, but with the correct pinned version. If this artifact set does not pin a version for the input artifact, this just returns the original coordinate. :rtype: M2Coordinate """

    coord = self._key(artifact)
    if coord in self._artifacts_to_versions:
      return self._artifacts_to_versions[coord]
    return artifact