code: def has_header_value (headers, name, value):
      
      name = name.lower()
      value = value.lower()
      for hname, hvalue in headers:
          if hname.lower()==name and hvalue.lower()==value:
              return True
      return False
docs: Look in headers for a specific header name and value.
      Both name and value are case insensitive.
  
      @return: True if header name and value are found
      @rtype: bool