parameters: (self, header)
return_statement: return -1
docstring: Return the index of the header in the set or return -1 if not found.
  
          :param header: the header to be looked up.
docstring_summary: Return the index of the header in the set or return -1 if not found.
docstring_tokens: Return the index of the header in the set or return - 1 if not found .
function: def find(self, header):
          """Return the index of the header in the set or return -1 if not found.
  
          :param header: the header to be looked up.
          """
          header = header.lower()
          for idx, item in enumerate(self._headers):
              if item.lower() == header:
                  return idx
          return -1
function_tokens: def find ( self , header ) : header = header . lower ( ) for idx , item in enumerate ( self . _headers ) : if item . lower ( ) == header : return idx return - 1