input: Write a python function to find all phone numbers in a given text using regular expressions.
  assert find_phone_numbers('The following numbers belong to us: 888-555-0000, +1-217-543-1000.') == ['888-555-0000', '+1-217-543-1000']
  assert find_phone_numbers('Contact us at 123-456-7890 or 987-654-3210 for more information.') == ['123-456-7890', '987-654-3210']
  assert find_phone_numbers('No phone numbers here!') == []
  assert find_phone_numbers('+44 7911 123456, 020 7946 0958') == ['+44 7911 123456', '020 7946 0958']
output: def find_phone_numbers(text):
      import re
      pattern = r'\+?\d[\d\s-]+\d'
      return re.findall(pattern, text)