Keras.Predict into Dataframe

[Finpyth]

Hallo.

i'm working with multiple machine learning models.
I want to have all my predictions into a dataframe. The following is working for my other ml scripts(sklearn), expect for this one where i use Kera library.
It return the error: 'Exception: Data must be 1-dimensional'
My DataFrame for all my features is called 'feature_list' and all my targets is 'target_list'

import pandas as pd
import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt
import statsmodels.api as sm
import keras 
import tensorflow as tf
from keras.models import Sequential
from keras.layers import Dense
from sklearn.metrics import r2_score

period = df['2011-01-01':'2015-01-01']
X = np.array(period[feature_list])
predictions = pd.DataFrame()
for i in target_list:
    y = np.array(period[i])
    split = sm.add_constant(X)
    train_size = int(0.75*y.shape[0])

    train_features = X[:train_size]
    train_targets = y[:train_size]
    test_features = X[train_size:]
    test_targets = y[train_size:]

    model = Sequential()
    model.add(Dense(5,input_dim=train_features.shape[1],activation='relu'))
    model.add(Dense(5,activation='relu'))
    model.add(Dense(1,activation='linear'))
    model.compile(optimizer='adam', loss='mse')
    model.fit(X, y, epochs=5, verbose=0)
    print(i)
    predictions[i] = model.predict(X[train_size:])

if i remove '[i]' in 'predictions[i] = model.predict(X[train_size:])' in return some values, so i think the mistake is in the compiling in some way.

So how do i compile all my predictions into a dataframe for all my targets?

Best regards Fynpyth from Denmark.