input: Write a python function to validate a pipeline in Azure Machine Learning workspace.
  assert validate_pipeline(pipeline) is None
output: def validate_pipeline(pipeline):
      from azureml.core import Workspace
      from azureml.pipeline.core import Pipeline
      from azureml.exceptions import UserErrorException
      
      try:
          # Assuming 'pipeline' is an instance of Pipeline
          if not isinstance(pipeline, Pipeline):
              raise TypeError("The pipeline parameter is not a valid AzureML Pipeline instance.")
          
          # Assuming 'workspace' is a valid AzureML workspace object
          workspace = pipeline._workspace
          
          if not isinstance(workspace, Workspace):
              raise TypeError("The workspace associated with the pipeline is not a valid AzureML Workspace instance.")
          
          # Validate the pipeline
          pipeline.validate(workspace)
          
      except UserErrorException as e:
          raise ValueError(f"Pipeline validation failed: {str(e)}")
      except Exception as e:
          raise ValueError(f"An error occurred during pipeline validation: {str(e)}")