Maya Python code example on how to shift animation keys for an export

maya_shift_keys_on_export.py

from maya import cmds
import contextlib


@contextlib.contextmanager
def offsetted_keys(offset, nodes=None):
    if nodes is None:
        # Apply to all time-based animation curves (excluding driven keys)
        nodes = cmds.ls(type=("animCurveTL","animCurveTU","animCurveTA","animCurveTT"))
    try:
        cmds.keyframe(nodes, edit=True, relative=True, selected=False, timeChange=offset)
        yield
    finally:
        cmds.keyframe(nodes, edit=True, relative=True, selected=False, timeChange=-offset)


start = 30
with offsetted_keys(-start):
    # Implement your export logic here
    export()