input: Write a function to develop a regular expression in Python to match all numeric strings. The function should take a string as input and return True if the string is a valid numeric string, otherwise return False. If the input string is empty, the function should return False.
  
  assert match_numeric_string('123456789')==True
  assert match_numeric_string('abc123')==False
  assert match_numeric_string('')==False
  assert match_numeric_string('123.456')==False
  assert match_numeric_string('0')==True
output: def match_numeric_string(s):
      import re
      if s == "":
          return False
      return bool(re.fullmatch(r'\d+', s))