code: def parse_first_number(s):
      
      m = re.match('\s*.*?(\d+)', s)
      if m is None: return None
      return int(m.groups(1)[0])
docs: Parse the first number in the string we encounter.
      
      s - The string to parse.
      
          parse_first_number('123')
          >>> 123
          parse_first_number('   12 meters')
          >>> 12
          parse_first_number('area: 156 meters')
          >>> 156
          parse_first_number(' 1 2 3')
          >> 1
          parse_first_number('    ')
          >> None
  
      Returns an integer or None if no number could be found.