<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 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