input: Write a python function to extract phone numbers from a given text using regular expressions.
  assert extract_phone_numbers("Contact us at (123) 456-7890 or 987-654-3210.") == ["(123) 456-7890", "987-654-3210"]
  assert extract_phone_numbers("My number is 123 456 7890.") == ["123 456 7890"]
  assert extract_phone_numbers("Reach me at 123.456.7890 or at the office at (555) 123-4567.") == ["123.456.7890", "(555) 123-4567"]
output: import re
  
  def extract_phone_numbers(text):
      pattern = r'\(?\d{3}\)?[ .-]?\d{3}[ .-]?\d{4}'
      return re.findall(pattern, text)