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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def markdownify_operative_config_str(string):
 """Convert an operative config string to markdown format."""


  # TODO(b/37527917): Total hack below. Implement more principled formatting.
  def process(line):
    """Convert a single line to markdown format."""
    if not line.startswith('#'):
      return '    ' + line

    line = line[2:]
    if line.startswith('===='):
      return ''
    if line.startswith('None'):
      return '    # None.'
    if line.endswith(':'):
      return '#### ' + line
    return line

  output_lines = []
  for line in string.splitlines():
    procd_line = process(line)
    if procd_line is not None:
      output_lines.append(procd_line)

  return '\n'.join(output_lines)