Clears the attribute from this object.

def DeleteAttribute(self, attribute):
    """Clears the attribute from this object."""
    if "w" not in self.mode:
      raise IOError("Deleting attribute %s from read only object." % attribute)

    # Check if this object should be locked in order to delete the attribute.
    # NOTE: We don't care about locking when doing blind writes.
    if self.mode != "w" and attribute.lock_protected and not self.transaction:
      raise IOError("Object must be locked to delete attribute %s." % attribute)

    if attribute in self.synced_attributes:
      self._to_delete.add(attribute)
      del self.synced_attributes[attribute]

    if attribute in self.new_attributes:
      del self.new_attributes[attribute]

    # Does this represent a new version?
    if attribute.versioned and attribute.creates_new_object_version:
      self._new_version = True

    self._dirty = True