code: def get_header(headers, name, default=None):
      
      name = name.lower()
      for header in headers:
          if header[0].lower() == name:
              return header[1]
      return default
docs: Return the value of header *name*.
  
      The *headers* argument must be a list of ``(name, value)`` tuples. If the
      header is found its associated value is returned, otherwise *default* is
      returned. Header names are matched case insensitively.