old_contents: # Copyright (c) 2016 Cisco Systems
  # All Rights Reserved.
  #
  #    Licensed under the Apache License, Version 2.0 (the "License"); you may
  #    not use this file except in compliance with the License. You may obtain
  #    a copy of the License at
  #
  #         http://www.apache.org/licenses/LICENSE-2.0
  #
  #    Unless required by applicable law or agreed to in writing, software
  #    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  #    License for the specific language governing permissions and limitations
  #    under the License.
  
  
  class HashTreeException(Exception):
      """Base Hash Tree Exception."""
      message = "An unknown exception occurred."
  
      def __init__(self, **kwargs):
          try:
              super(HashTreeException, self).__init__(self.message % kwargs)
              self.msg = self.message % kwargs
          except Exception:
              self.msg = self.message
              raise
  
      def __str__(self):
          return self.msg
  
  
  class StructuredHashTreeException(HashTreeException):
      pass
  
  
  class MultipleRootTreeError(StructuredHashTreeException):
      message = ("Node with key %(key)s cannot be inserted in tree since "
                 "it's not nested in root %(root_key)s")
  
  
  class HashTreeNotFound(StructuredHashTreeException):
      message = "Hash Tree not found for tenans %(tenant_rn)s"
  
new_contents: # Copyright (c) 2016 Cisco Systems
  # All Rights Reserved.
  #
  #    Licensed under the Apache License, Version 2.0 (the "License"); you may
  #    not use this file except in compliance with the License. You may obtain
  #    a copy of the License at
  #
  #         http://www.apache.org/licenses/LICENSE-2.0
  #
  #    Unless required by applicable law or agreed to in writing, software
  #    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  #    License for the specific language governing permissions and limitations
  #    under the License.
  
  
  class HashTreeException(Exception):
      """Base Hash Tree Exception."""
      message = "An unknown exception occurred."
  
      def __init__(self, **kwargs):
          try:
              super(HashTreeException, self).__init__(self.message % kwargs)
              self.msg = self.message % kwargs
          except Exception:
              self.msg = self.message
              raise
  
      def __str__(self):
          return self.msg
  
  
  class StructuredHashTreeException(HashTreeException):
      pass
  
  
  class MultipleRootTreeError(StructuredHashTreeException):
      message = ("Node with key %(key)s cannot be inserted in tree since "
                 "it's not nested in root %(root_key)s")
  
  
  class HashTreeNotFound(StructuredHashTreeException):
      message = "Hash Tree not found for tenants %(tenant_rn)s"
  
subject: Fix typo in hashtree/exceptions.py