def _is_H2O_mass_tuple(self, value):
if not type(value) is tuple:<EOL><INDENT>return False<EOL><DEDENT>elif not len(value) == <NUM_LIT:2>:<EOL><INDENT>return False<EOL><DEDENT>elif not type(value[<NUM_LIT:0>]) is str and not value[<NUM_LIT:0>] == "<STR_LIT>":<EOL><INDENT>return False<EOL><DEDENT>elif not type(value[<NUM_LIT:1>]) is float andnot type(value[<NUM_LIT:1>]) is numpy.float64 andnot type(value[<NUM_LIT:1>]) is numpy.float32:<EOL><INDENT>return False<EOL><DEDENT>else:<EOL><INDENT>return True<EOL><DEDENT>
Determines whether value is a tuple of the format
(size class(float), mass(float)).

:param value: The value to check.

:returns: Whether the value is a tuple in the required format.