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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def cp(source, bucket, checksum, key_prefix):
 """Create new bucket from all files in directory."""

    from .models import Bucket
    from .helpers import populate_from_path
    for object_version in populate_from_path(
            Bucket.get(bucket), source, checksum=checksum,
            key_prefix=key_prefix):
        click.secho(str(object_version))
    db.session.commit()