docs: def get_process_definition_start(fname, slug):
      """Find the first line of process definition.
  
      The first line of process definition is the line with a slug.
  
      :param str fname: Path to filename with processes
      :param string slug: process slug
      :return: line where the process definiton starts
      :rtype: int
  
      """
      with open(fname) as file_:
          for i, line in enumerate(file_):
              if re.search(r'slug:\s*{}'.format(slug), line):
                  return i + 1
      # In case starting line is not found just return first line
      return 1