<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def strip_prefix(string, prefix):
 """Returns a copy of the string from which the multi-character prefix has been stripped. Use strip_prefix() instead of lstrip() to remove a substring (instead of individual characters) from the beginning of a string, if the substring is present. lstrip() does not match substrings but rather treats a substring argument as a set of characters. :param str string: The string from which to strip the specified prefix. :param str prefix: The substring to strip from the left of string, if present. :return: The string with prefix stripped from the left, if present. :rtype: string """

  if string.startswith(prefix):
    return string[len(prefix):]
  else:
    return string