TypeError('No suitable SharedVariable constructor could be found.') Using lasagne and theano

Question

Hi i'm currently learning coding with python and have been following a tutorial series which has helped me make the code i will show below. Apologies for it being so long but I cannot pinpoint the line of code which is causing this error. I have removed a lot of the commenting to reduce the amount of code posted.

import numpy as np
import urllib.request
import os
import gzip
import lasagne
import theano
import theano.tensor as T


def load_dataset():
    def download(filename, source="http://yann.lecun.com/exdb/mnist/"):
        print("downloading:", filename)
        urllib.request.urlretrieve(source+filename, filename)

def load_mnist_images(filename):
    if not os.path.exists(filename):
        download(filename)
        
    with gzip.open(filename, "rb") as f:
        data = np.frombuffer(f.read(), np.uint8, offset= 16)
        data = data.reshape(-1, 1, 28, 28)

        return data / np.float32(256)

def load_mnist_labels(filename):
    if not os.path.exists(filename):
        download(filename)
    with gzip.open(filename, "rb") as f:
        data = np.frombuffer(f.read(), np.uint8, offset= 8)
    return data


x_train = load_mnist_images("train-images-idx3-ubyte.gz")
y_train = load_mnist_labels("train-labels-idx1-ubyte.gz")
x_test = load_mnist_images("t10k-images-idx3-ubyte.gz")
y_test = load_mnist_labels("t10k-labels-idx1-ubyte.gz")

return x_train, y_train, x_test, y_test

x_train, y_train, x_test, y_test = load_dataset()

###### creating the handwriting digit recognition code ######

def build_nn(input_var = None):

l_in = lasagne.layers.InputLayer(shape=(None,1,28,28), input_var=input_var)

l_in_drop = lasagne.layers.DropoutLayer(l_in, p=0.2)

l_hid1 = lasagne.layers.DenseLayer(l_in_drop, num_units= 800, 
                                nonlinearity= lasagne.nonlinearities.rectify,
                                W= lasagne.init.GlorotUniform())

l_hid1_drop = lasagne.layers.DropoutLayer(l_hid1, p=0.5)
l_hid2 = lasagne.layers.DenseLayer(l_hid1_drop, num_units= 800, 
                                nonlinearity= lasagne.nonlinearities.rectify,
                                W= lasagne.init.GlorotUniform())

l_hid2_drop = lasagne.layers.DropoutLayer(l_hid2, p=0.5)

l_out = lasagne.layers.DenseLayer(l_hid2_drop, num_units=10, 
                                nonlinearity= lasagne.nonlinearities.softmax)
return l_out 

input_var = T.tensor4("inputs") # an empty 4d array
target_var = T.ivector("targets") # an empty 1d int array to represent the labels

network = build_nn(input_var) # call the func that initializes the neural network

prediction = lasagne.layers.get_output(network)
loss = lasagne.objectives.categorical_crossentropy(prediction, target_var)
loss = loss.mean()
params = lasagne.layers.get_all_params(network, trainable=True)
updates = lasagne.updates.nesterov_momentum(loss, params, learning_rate=0.01, momentum=0.9)
train_fn = theano.function([input_var, target_var], loss, updates= updates)

num_training_steps = 10

for step in range(num_training_steps):
    train_err = train_fn(x_train, y_train)
    print("current training step is " + str(step))

The error that's stopping this code is this:

Traceback (most recent call last):

  File "C:\Users\Admin\.vscode\Practice codes\machine learning\deep learning\deep learning.py", line 125, in <module>
    network = build_nn(input_var) # call the func that initializes the neural network

  File "C:\Users\Admin\.vscode\Practice codes\machine learning\deep learning\deep learning.py", line 95, in build_nn
    l_hid1 = lasagne.layers.DenseLayer(l_in_drop, num_units= 800,

  File "C:\Users\Admin\AppData\Roaming\Python\Python38\site-packages\lasagne\layers\dense.py", line 103, in __init__
    self.W = self.add_param(W, (num_inputs, num_units), name="W")

  File "C:\Users\Admin\AppData\Roaming\Python\Python38\site-packages\lasagne\layers\base.py", line 234, in add_param
    param = utils.create_param(spec, shape, name)

  File "C:\Users\Admin\AppData\Roaming\Python\Python38\site-packages\lasagne\utils.py", line 393, in create_param
    spec = theano.shared(spec, broadcastable=bcast)

  File "C:\Users\Admin\AppData\Roaming\Python\Python38\site-packages\theano\compile\sharedvalue.py", line 284, in shared
    raise TypeError('No suitable SharedVariable constructor could be found.'

TypeError: No suitable SharedVariable constructor could be found. Are you sure all kwargs are supported? We do not support the parameter dtype or type. value="[[ 0.04638761 -0.02959769  0.02330909 ...  0.01545383  0.04763002
   0.05265676]
 [ 0.02095251 -0.05393376 -0.04289599 ... -0.02409102  0.02824548
  -0.00327342]
 [ 0.02908951 -0.02853872 -0.05450716 ... -0.02296509  0.02495853
   0.02486875]
 ...
 [-0.03704383  0.0286258   0.01158947 ... -0.02583007 -0.04925423
  -0.0470493 ]
 [ 0.03230407 -0.00246115 -0.05074456 ...  0.00299953  0.01883504
   0.01312843]
 [-0.05762409 -0.05119916 -0.02820581 ... -0.05675326  0.00458562
   0.04403118]]". parameters="{'broadcastable': (False, False)}"

If it helps I'm using python 3.8 - lasagne 0.2.dev1 - theano 1.0.5.
Any help would be greatly appreciated, any questions feel free to ask.
Thanks in advance