old_contents: """make labels unique
  
  Revision ID: 264ddaebdfcc
  Revises: 89ff8a6d72b2
  Create Date: 2018-03-12 11:15:09.729850
  
  """
  
  from alembic import op
  # import sqlalchemy as sa
  
  
  # revision identifiers, used by Alembic.
  revision = '264ddaebdfcc'
  down_revision = '89ff8a6d72b2'
  branch_labels = ('hil')
  
  # pylint: disable=missing-docstring
  
  
  def upgrade():
      op.create_unique_constraint(None, 'network', ['label'])
      op.create_unique_constraint(None, 'node', ['label'])
      op.create_unique_constraint(None, 'project', ['label'])
      op.create_unique_constraint(None, 'switch', ['label'])
  
  
  def downgrade():
      op.drop_constraint(None, 'switch', type_='unique')
      op.drop_constraint(None, 'project', type_='unique')
      op.drop_constraint(None, 'node', type_='unique')
      op.drop_constraint(None, 'network', type_='unique')
  
new_contents: """make labels unique
  
  Revision ID: 264ddaebdfcc
  Revises: 89ff8a6d72b2
  Create Date: 2018-03-12 11:15:09.729850
  
  """
  
  from alembic import op
  # import sqlalchemy as sa
  
  
  # revision identifiers, used by Alembic.
  revision = '264ddaebdfcc'
  down_revision = '89ff8a6d72b2'
  branch_labels = ('hil',)
  
  # pylint: disable=missing-docstring
  
  
  def upgrade():
      op.create_unique_constraint(None, 'network', ['label'])
      op.create_unique_constraint(None, 'node', ['label'])
      op.create_unique_constraint(None, 'project', ['label'])
      op.create_unique_constraint(None, 'switch', ['label'])
  
  
  def downgrade():
      op.drop_constraint(None, 'switch', type_='unique')
      op.drop_constraint(None, 'project', type_='unique')
      op.drop_constraint(None, 'node', type_='unique')
      op.drop_constraint(None, 'network', type_='unique')
  
subject: add a trailing comma for the tuple