input: from typing import List
  
  def match_numeric_strings(strings: List[str]) -> List[str]:
      """
      Given a list of strings, return a list of all strings that match the regular expression for numeric strings.
      >>> match_numeric_strings(['123456789', 'abc123', '987654321', '1a2b3c'])
      ['123456789', '987654321']
      """
      import re
      pattern = '^[0-9]+$'
      return [s for s in strings if re.match(pattern, s)]
output:     import re
      pattern = '^[0-9]+$'
      return [s for s in strings if re.match(pattern, s)]