as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
construct a regular expression to validate a valid phone number.
user
^\s*(\+?[\d]{1,4})?[\s-]?\(?[\d]{3}\)?[\s-]?[\d]{3}[\s-]?[\d]{4}\s*$
assistant