import importlib


class PseudoDB:
    def __init__(self, datasource="default.data"):
        self.datasource = datasource
        self.data = self.load_data()

    def load_data(self):
        module_name = self.datasource.replace('.py', '')
        try:
            module = importlib.import_module(module_name)
            return module
        except ImportError:
            print(f"Data module '{module_name}' not found.")
            return None

    def data_list(self):
        # Check if default has been successfully loaded
        if self.data is not None:
            attr_names = []
            for attr_name in dir(self.data):
                if not attr_name.startswith('__'):
                    attr_names.append(attr_name)
            return attr_names
        else:
            return []

    def collections(self, attr_name):
        if self.data is not None:
            return getattr(self.data, attr_name)
        else:
            return None

    def get_keys(self, attr_name):
        if self.data is not None:
            collection = getattr(self.data, attr_name)
            if isinstance(collection, dict):
                return list(collection.keys())
            else:
                return {}

    def get_values(self, attr_name, key):
        if self.data is not None:
            collection = getattr(self.data, attr_name)
            if isinstance(collection, dict):
                return list(collection[key])
            else:
                return collection
        else:
            return None