<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def is_builtin_css_function(name):
 """Returns whether the given `name` looks like the name of a builtin CSS function. Unrecognized functions not in this list produce warnings. """

    name = name.replace('_', '-')

    if name in BUILTIN_FUNCTIONS:
        return True

    # Vendor-specific functions (-foo-bar) are always okay
    if name[0] == '-' and '-' in name[1:]:
        return True

    return False