in fxa/core.py [0:0]
def _get_stretched_password(self, email, password=None, stretchpwd=None):
if password is not None:
if stretchpwd is not None:
raise ValueError("must specify exactly one of 'password' or 'stretchpwd'")
stretchpwd = quick_stretch_password(email, password)
elif stretchpwd is None:
raise ValueError("must specify one of 'password' or 'stretchpwd'")
return stretchpwd