input: Write a python function to extract all numbers (both integers and floating-point) from a given string using regular expressions.
  assert extract_numbers("There are 45.8 apples and 12.3 oranges.") == ['45.8', '12.3']
  assert extract_numbers("I have 2 cats, 3 dogs, and 1.5 parrots.") == ['2', '3', '1.5']
  assert extract_numbers("The price is -99.99 dollars and +100 euros.") == ['-99.99', '+100']
output: def extract_numbers(text):
      import re
      return re.findall(r'[+-]?\d*\.?\d+', text)