attempt to index local 'params' (a nil value) error - indexing

Question

This is the full Error
src/states/game/PlayState.lua:21: attempt to index local 'params' (a nil value)
This is the Code where the error occurs, on the line where we call levelmaker.generate specificaly because of params.levelwidth.
function PlayState:enter(params)
self.level = LevelMaker.generate(params.levelwidth or 100, 10, self.levelcount)
self.tileMap = self.level.tileMap
self.levelcount = 1 or params.level
self.player = Player({
x = 0, y = 0,
width = 16, height = 20,
texture = 'green-alien',
stateMachine = StateMachine {
['idle'] = function() return PlayerIdleState(self.player) end,
['walking'] = function() return PlayerWalkingState(self.player) end,
['jump'] = function() return PlayerJumpState(self.player, self.gravityAmount) end,
['falling'] = function() return PlayerFallingState(self.player, self.gravityAmount) end
},
map = self.tileMap,
level = self.level,
score = params.score or 0
})
self:spawnEnemies()
self.player:changeState('falling')
end
The function is from called here and I also pass the params from here:
function generatePole(width, flagPoleColor, Ypos, Xpos, part)
return GameObject {
texture = 'flags',
x = (Xpos - 1) * TILE_SIZE,
y = (Ypos - 1) * TILE_SIZE - 4,
width = 6,
height = 16,
frame = flagPoleColor + part * FLAG_OFFSET,
collidable = true,
consumable = true,
solid = false,
onConsume = function(player, object)
gSounds['pickup']:play()
player.score = player.score + 250
gStateMachine:change('play', {
score = player.score,
levelwidth = levelwidth + 10,
level = levelcounter + 1
})
end
}
end
This is my state machine in which the function gstatemachine:change is written.
StateMachine = Class{}
function StateMachine:init(states)
self.empty = {
render = function() end,
update = function() end,
enter = function() end,
exit = function() end
}
self.states = states or {} -- [name] -> [function that returns states]
self.current = self.empty
end
function StateMachine:change(stateName, enterParams)
assert(self.states[stateName]) -- state must exist!
self.current:exit()
self.current = self.states[stateName]()
self.current:enter(enterParams)
end
function StateMachine:update(dt)
self.current:update(dt)
end
function StateMachine:render()
self.current:render()
end