Array is not loaded on the pdal data pipeline

Question

Recently, I made the data pipeline that process the cloud point data. The data format is .las file and it was classified data. So I used the pdal to process the data for train the model. But when I load the data from pipeline, the silence error occurred.

here are my code.

import pdal
import numpy as np

pipeline_def = """
{
  "pipeline": [
    {
      "type": "readers.las",
      "filename": "input.las"
    }
  ]
}
"""
print("0")
pipeline = pdal.Pipeline(pipeline_def)
print("1")
try:
    print("2")
    pipeline.execute()
    arrays = pipeline.arrays
    array = arrays[0]
except Exception as e:
    print('An error occurred:', str(e))

They printed "2" but after that running was stopped with no error message.

So I added this code and rerun the code.

...
print("0")
pipeline = pdal.Pipeline(pipeline_def)
print("1")
try:
    print("2")
    pipeline.execute()
    print("3")
    metadata = pipeline.metadata
    print(metadata)
    pipeline.execute()
    arrays = pipeline.arrays
    array = arrays[0]
...

And they print the metadata correctly. And the error message occurred like this.

An error occurred: bad allocation

Hope anyone help me.