# En __init__.py del paquete que contiene AtomPositionManager
try:
    from sage_lib.AtomPositionManager import AtomPositionManager
except ImportError as e:
    import sys
    sys.stderr.write(f"An error occurred while importing AtomPositionManager: {str(e)}\n")
    del sys

try:
    import numpy as np
except ImportError as e:
    import sys
    sys.stderr.write(f"An error occurred while importing numpy: {str(e)}\n")
    del sys

# Subclase para sistemas no periódicos
class NonPeriodicSystem(AtomPositionManager):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)

    def read_PDB(self, file_path):
        # Implementación
        pass

    def convert_to_periodic(self):
        return PeriodicSystem(**self.attributes)
