new_contents: """empty message
  
  Revision ID: bf1347acdee2
  Revises: b4dd0add5f79
  Create Date: 2018-03-23 17:08:11.289953
  
  """
  from alembic import op
  import sqlalchemy as sa
  
  
  # revision identifiers, used by Alembic.
  revision = 'bf1347acdee2'
  down_revision = 'b4dd0add5f79'
  branch_labels = None
  depends_on = None
  
  
  def upgrade():
      # ### commands auto generated by Alembic - please adjust! ###
      op.add_column('task_type', sa.Column('for_entity', sa.String(length=10), nullable=True))
      op.drop_constraint('task_type_uc', 'task_type', type_='unique')
      op.create_unique_constraint('task_type_uc', 'task_type', ['name', 'for_entity', 'department_id'])
      # ### end Alembic commands ###
  
  
  def downgrade():
      # ### commands auto generated by Alembic - please adjust! ###
      op.drop_constraint('task_type_uc', 'task_type', type_='unique')
      op.create_unique_constraint('task_type_uc', 'task_type', ['name', 'department_id'])
      op.drop_column('task_type', 'for_entity')
      # ### end Alembic commands ###
  
subject: Add migration file