plugin XEP-0166, XEP-0167, XEP-0234, XEP-0353: call events management to prepare for UI: - XEP-0166: add `jingle_preflight` and `jingle_preflight_cancel` methods to prepare a jingle session, principally used by XEP-0353 to create and cancel a session - XEP-0167: preflight methods implementation, workflow split in more methods/signals to handle UI and call events (e.g.: retract or reject a call) - XEP-0234: implementation of preflight methods as they are now mandatory - XEP-0353: handle various events using the new preflight methods rel 423

"""${message}

Revision ID: ${up_revision}
Revises: ${down_revision | comma,n}
Create Date: ${create_date}

"""
from alembic import op
import sqlalchemy as sa
${imports if imports else ""}

# revision identifiers, used by Alembic.
revision = ${repr(up_revision)}
down_revision = ${repr(down_revision)}
branch_labels = ${repr(branch_labels)}
depends_on = ${repr(depends_on)}


def upgrade():
    ${upgrades if upgrades else "pass"}


def downgrade():
    ${downgrades if downgrades else "pass"}