code: def upgrade():
      with op.batch_alter_table("slices") as batch_op:
          batch_op.add_column(
              sa.Column("query_context", sa.Text(), nullable=True)
          )
  
imports: import sqlalchemy
  from alembic import op
  from sqlalchemy.dialects import mysql
label_desc: Use image node_id 1 for calling a global function with example usage: upgrade() without return types