How can I write double (Greek) indices using LaTeX

I am attempting to write a set of functions that could print out symbols with an upper index and two (or more) lower indices using SymPy; however, I've been attempting to get past a problem.

Here's a minimal example:

import sympy as smp
from IPython.display import display, Latex
smp.init_printing()

t, r, theta, phi = smp.symbols(r't, r, \theta, \phi')

display(Latex(smp.latex(fr'$\Lambda^{r}_{t}{t}$')))

Prints this (In a Jupyter Notebook Environment):

However, I want the t to be an index too, so the Lambda symbol would have two lower indices instead of one.

Another related problem arises when I try using the theta and phi symbols as indices:

display(Latex(smp.latex(fr'$\Lambda^{phi}_{theta}{r}$')))

Which prints (Again, in a Jupyter Notebook Environment):

In order to fix this, I had to put a space between the symbols:

display(Latex(smp.latex(fr'$\Lambda^{phi}_{theta} {r}$')))

Which, unfortunately, also prints:

Edit:

I've attempted @geofisue's fix, and it prints this:

Found a fix!

I had to create a custom class inheriting from the Indexed and IndexedBase sympy classes, and edit it to fit my needs. My example code now looks like so:

import sympy as smp
from IPython.display import display
smp.init_printing()

class CustomIndexed(smp.Indexed):
    def _latex(self, printer):
        return '%s^{%s}_{{%s}{%s}}' % (
            self.base, *self.indices
        )
    
class CustomIndexedBase(smp.IndexedBase):
    def __getitem__(self, indices, **kwargs):
        return CustomIndexed(self.name, 
                             *indices)

t, r, theta, phi = smp.symbols(r't, r, \theta, \phi')

Lambda = CustomIndexedBase(r'\Lambda')

display(Lambda[r, phi, theta])

Which displays the correct symbol:

Indexed Symbol (Correct)

The issue with your methods is the curly brackets. You have two options.

1. Wrap all the subscript terms in double curly brackets. The double curly brackets are necessary for the f-string to know which curly brackets are for replacement and which are to stay as curly brackets in the final string. You need the curly brackets to stay so that LaTeX knowns that both those terms are in the subscript.
2. Use a double subscript. This isn't technically valid LaTeX (if you tried it on Overleaf you'd get an error), but it seems to work for sympy.

import sympy as sp
from IPython.display import display 

t, r, theta, phi, Lambda = sp.symbols("t r \\theta \\phi \\Lambda")
symbol = sp.symbols(f"{Lambda}^{r}_{{{phi}{theta}}}")  # method 1
#symbol = sp.symbols(f"{Lambda}^{r}_{phi}_{theta}")    # method 2
display(symbol)