Nim two key tables with generics

Attempting to create a two-valued dictionary in Nim where value is a user-specified type.

import Tables

type
  TwoKeyTable[T] = Table[string, Table[string, T]]

# initialize two key table
proc initTwoKeyTable[T](): TwoKeyTable[T] =
  result = initTable[string, Table[string, T]]()  

# check to see if keys k1 and k2 are in table
proc hasKeyPair[T](tkTable: TwoKeyTable[T], k1, k2: string): bool =
  result = false
  # check if first key is in table
  if not tkTable.hasKey(k1):
    return
  # check if second key in the tables
  if not tkTable[k1].hasKey(k2): # 1st error coming from here 
    return
  result = true

# add a value corresponding to the keys k1 and k2
proc addKeyPairValue[T](tkTable: var TwoKeyTable[T], k1, k2: string, val: T) =
  if not tkTable.hasKey(k1):
    tkTable[k1] = initTable[string, T]() # 2nd error coming from here
  tkTable[k1][k2] = val


var tkTable = initTwoKeyTable[int]()
echo tkTable.hasKeyPair("a", "b") # produces the 1st error

      

        
        
        
      

    

Which gave the following error:

lib/pure/collections/tables.nim(249, 38) Error: type mismatch: got (Table[system.string, system.int]) but expected 'int

      

        
        
        
      

    

I also have a problem with this.

var tkTable = initTwoKeyTable[int]()
tkTable.addKeyPairValue("a", "b", 1) # produces the 2nd error

      

        
        
        
      

    

Which gives the same error.