# Import os
import os
# Import arcpy module
import arcpy
# Set the workspace
arcpy.env.workspace = r"C:\ChartSchema.gdb"
# Use the ListDatasets function to return a list of feature datasets then list of feature classes
datasets = arcpy.ListDatasets(feature_type='feature')
featureclasses = arcpy.ListFeatureClasses(feature_dataset='Nautical')
# Use the list of feature classes for Apply Maritime Symbology tool
arcpy.maritime.ApplyMaritimeSymbology(featureclasses,r'C:\ProductFiles\ArcGIS Maritime\Product Files\3.1\Charting\INT1.cxml')
$desktopversion\cmsfiles\py\Maritime\ApplyMaritimeSymbology.py