code: def upgrade():
      op.create_table(
          "css_templates",
          sa.Column("created_on", sa.DateTime(), nullable=False),
          sa.Column("changed_on", sa.DateTime(), nullable=False),
          sa.Column("id", sa.Integer(), nullable=False),
          sa.Column(
              "template_name", sa.String(length=250), nullable=True
          ),
          sa.Column("css", sa.Text(), nullable=True),
          sa.Column("changed_by_fk", sa.Integer(), nullable=True),
          sa.Column("created_by_fk", sa.Integer(), nullable=True),
          sa.ForeignKeyConstraint(["changed_by_fk"], ["ab_user.id"]),
          sa.ForeignKeyConstraint(["created_by_fk"], ["ab_user.id"]),
          sa.PrimaryKeyConstraint("id"),
      )
  
imports: import sqlalchemy
  from alembic import op
label_desc: Use image node_id 1 for calling a global function with example usage: upgrade() without return types