input: Write a python function to execute a series of commands to process sequencing data as described in the provided script, handling different protocols (miramito/quickmito/seedmito) and creating output files.
  assert process_sequencing_data(100, "file_list.txt", "reference.fa", "miramito", 15) == "expected_output_miramito.fa"
  assert process_sequencing_data(200, "file_list.txt", "reference.fa", "quickmito", 10) == "expected_output_quickmito.fa"
  assert process_sequencing_data(300, "file_list.txt", "reference.fa", "seedmito", 5) == "expected_output_seedmito.fa"
output: import subprocess
  
  def process_sequencing_data(sample_size, file_list, reference, protocol, threshold):
      output_file = f"expected_output_{protocol}.fa"
      
      if protocol == "miramito":
          command = f"miramito -s {sample_size} -i {file_list} -r {reference} -t {threshold} -o {output_file}"
      elif protocol == "quickmito":
          command = f"quickmito -s {sample_size} -i {file_list} -r {reference} -t {threshold} -o {output_file}"
      elif protocol == "seedmito":
          command = f"seedmito -s {sample_size} -i {file_list} -r {reference} -t {threshold} -o {output_file}"
      else:
          raise ValueError("Unknown protocol")
      
      subprocess.run(command, shell=True, check=True)
      
      return output_file